Also, the entire article would be much clearer with plain language. Analogies are overrated and ELI5 method actually hurts in grasping complex abstract topics.
I should correct myself and say that Analogies are "Overused". Feynman's teaching style had frequent use of Analogies but as a way to clarify the concept, not manifest the concept using an analogy in a didactic manner to students. He explained things in plain english first.
Analogies definitely have a place in learning but it should be carefully prefaced with a warning that analogies can only go so far. You can't explain Quantum Electrodynamics using analogies or you're misleading the students.
I think the whole purpose of ELI5, when done right, is to introduce you to the concept. Not help you master it. Similarly, analogies do help, especially for a non-native speaker.
I'm not entirely sure this is true wrt the gender thing, one could easily substitute grandpa and it would still make the same sense. As far as being discriminatory against age, I really can't see how you came to that point. Perhaps assuming that old people don't get technology in general might be an unfair assumption as there are plenty of those in that age range who do get it, but I don't think that makes it wrong to use such a conception.
At that, I don't particularly think it's being discriminatory at all. It isn't perpetuating some ideal that all old people or all females just don't get the idea of databases. This comment sorta strikes me as unnecessarily reactionary, rather than focusing on the content and substance of the article.
I think it's safe to assume that, in large part, the very old and the very young are both more likely to not understand (or care about) technical details.