Eli5: Why do you use “they” for non-gendered speech instead of “it”?

Question

I’m not a native speaker, but as far as I understood, for singular objects and animals “it” was used. Why use “they” for individual people then?

In: 1400

Answer 1

some people do use it/its pronouns but that’s much rarer than they/them and unless you’ve been asked to use them many people consider it dehumanizing language