It helps to understand how it actually works. The s in its does not point towards possession, it is simply part of the word "its".
My, His, Hers, Ours, Yours, Theirs, Its.
Not Me's, He's, She's, Us's, Your's, Their's, It's.
English is an easy language. Most languages use a lot more words than all that to convey all that. English speakers don't have to deal with the singular second person, with a separate objective noun for you/he/she, with neutrals (heck, barely at all with the feminine), and so on.
The brain is an incredible pattern recognition machine.
The regular form of possessive is 's. That is, when it's right to add an s to a noun indicate possession we add an apostrophe. This is more regular than a lot of english rules. So now there are pronouns. They are a bit weird, carrying some strange stuff from germanic languages about changing the word based on the case (sometimes). For the most part, it's pretty straightforward still.
Now we get to the word its. Yeah, it's a pronoun, but it follows the possessive pattern of adding an s. So 'it' follows the pronoun pattern of changing the word, but it also phonetically follows the regular noun pattern of adding an s.
In this one special case, there are two patterns being followed at the same time. Except not really, because unlike all the other cases where the s is appended for possession, we don't mark it different.
This is of course because there is a form of the phonetic 'its', which is spelled "it's" . This word is very similar to its, but it really is a contraction (a special word that actually means two words, but we're lazy and drop some of letters from the second word) in this case, "it's" is ("it's"'s :) ) short for it is. That phrase of course is not about possession, but it does describe a quality possessed by the thing referred to by "it".
Of course on top of all this, we have yet another use in english for the 's construct. It is related to the "it's", because it not only denotes possession, but also denotes a contraction with is, or with has (which itself is a completely different rant - have and is are arbitrarily used in all sorts of languages) like described above for it's , but more generally.
That means the the sentence:
Bob's going to Bob's house.
Is a correct way of using the 's in two different meanings...
Bob is going to the house Bob owns.
Yet, if was talking about a robot...
Robot is going home. Its house has its charger and it's going to plug in.
So yeah, English is super duper easy! I mean, how hard is it for our pattern matching machines to not realize that contracting with is means 's, that possession which is phonetically an s sound is spelled 's, and pronouns use different words for different cases, these are all pretty regular occurrances, EXCEPT when talking about spelling the pronoun its, which despite its appearance and phonetics of being a pronoun that follows noun rules, is actually a separate word arbitrarily. I mean, who would ever get confused by the 's pattern not applying in this one case? It's a special case of a special case and should be extremely obvious.
I know you're being snarky, but do you actually speak any other languages? Because I don't think you realize how easy you have it.
He. She. It. That's all you have to deal with. You have to know whether the subject is male, female, or indeterminate in some way. There's maybe a couple of exception (like boats being refered to as She and such) but other than that, you literally go by genitalia.
In most other languages you have to take into account whether the subject is male or female and whether the subject should be referred to as plural as a form of politeness; if their sex is unknown or indeterminate you have to know whether the word itself is masculine or feminine (or neutral!). Shall I go on?
Oh and that's not even mentioning languages with different grammar rules for the various different kind of persons. You have singular and plural. That's it. Some languages have singular, plural-few, plural-many, some, none, all, and they all have their different grammatical rules.
Boo-hoo, you gotta remember whether to put an s or not. Some languages have to remember dozens of different suffixes to put at the end of the word depending on the forementioned rules and a bunch more, including how the word itself is written.
To be considered competent in written English you also have to master a system of orthography so preposterously inconsistent and divorced from the spoken language that native-speaking kids have competitions to show off their prowess at rote-learning spellings of words; far more challenging than remembering whether the nouns are der, die oder das. In many other languages, literacy involves memorizing a few basic rules and knowing how words sound.
Given the vast amount of energy wasted on memorizing spelling quirks, compared with nearly all other languages, it's not surprising that many people, including you, frequently make other mistakes in their written English. When a language consists more of exceptions than rules one can't be too harsh on people for wrongly applying a rule.
To use the programming language you used elsewhere: English is PHP... it's easy to use as badly as everybody else uses it.
Argh... now I really got it backwards. What I meant to say was that one does not write "shes", one writes "her", and not "wes" but "our". And that does not apply to "it".
To summarize, comparison to other personal pronouns is irrelevant since "it" has a special combination of rules.
I'm not sure how "it" is special". Because its possessive ends in an s? So do "theirs", "hers", and "ours" (which I think are the ones you meant).
I think you're having a hard time because you're overcomplicating the matter. "its" is the possessive of "it". "it's" is a contraction of "it is". Possessives adjectives: My, Your, His, Her, Their, Its. Possessive pronouns: Mine, Yours, His, Her, Theirs, Its. You have four less to remember than with most languages :)
All English pronouns are nonstandard, different from each other, and different from nouns. You can bother to learn it or not, you're choice. I mean your choice. Yer?
Part of why English is everywhere is because it is extremely flexible, malleable and very lax about its own rules. Otherwise we'd all be speaking French.
I prefer to see English like I see Python. Younger, easier, more flexible and more self-aware than the languages it draws its roots from, and fun enough that it has a lot of influence on every other language.
I think people coming from other languages have another view of English. As a "swede" I find it surprisingly logical and easy to learn. I bet someone from Finland would agree :-)
You're at an advantage. Swedish is essentially just an antiquated english (I mean that in a good way). The difference in learning Swedish between before and after I learned English was night on pluto and day on venus.
I think OP was just being an ass, but whether the behavior is opposite really depends on your frame of reference. The lack of apostrophe is consistent with how you deal with possessive pronouns: his, her/hers, our/ours, etc. No possessive pronouns have apostrophes, with one exception. And the apostrophe is consistent with how other contractions work.
If you remember (and care) that its and it's are two separate words, then you should be able think your way through it. It's could legitimately be possessive or a contraction, but its can only be the possessive.
Anyway, I agree with you that it's tricky enough that we shouldn't be assholes about it.
* ...about to be placed in Fat Man's casing.
* ...about to be placed in the bomb's casing
* ... about to be placed in its casing.
One of those is not like the others.