Actually I think the correctness of using a singular they is disputed but I am not a grammaticist, however the word cromulent which you used is not even a real word but I didn't mention the correction to do all that nitpicking, I just thought since the person's information is accessible, it'd be nice to refer to him correctly that's all.
Only to a prescriptivist[1] trying to keep the language static. "Cromulent" is slowly making its way into descriptivist[1] dictionaries and is recognized about as often as any other new word, so it just as much a "real" word as other new words ("email", "google" (transitive verb), "truthiness").
> the correctness of using a singular they
The alternative is gendered pronouns which have several problems[2].
/* I'm not trying to nitpick your post; I just thought these two Tom Scott clips were fun and relevant to these grammar issues. */
That was kinda my point, I was not nitpicking -relative OP's- grammatical usage, I just thought it was convenient to refer to the author in a more specific manner since his details were obvious. I had no idea whether their -relative OP- :) intention was to use "their" in a singular or plural manner. Heck, one of my favorite Stephen Fry videos [0] talks exactly about this!
"Correctness" of word choice is determined by usage. I prefer a consensus where "they" is accepted as being possibly singular, so when I have no reason not to, I choose to treat it as being a correct usage.
I also tend to use it sometimes despite knowing the gender of the person I am referring to. This seems reasonable to me, because I don't see any reason why it is important to always specify the person's gender, when I don't need to specify who the person is, and doing so allows me to refer to someone without specifying a gender, should any situation occur where that would be useful, without anyone commenting on my word choice, because I would already be in the habit of sometimes leaving it out.
It is also happens to be consistent with the way most academics refer to work, right? A single author will use "we" and others will use "they" to refer their work.