That's not the surprising part at all, but I think you knew that.
The surprising part is that, as easy as it is to use the right pronouns after being corrected, some people refuse to.
This was your original post:
I'm addressing what I think is a pretty ridiculous false-equivalence. You ought to know exactly why people behave differently with dogs; because there is no meaningful distinction between gender and biological sex.
Just because something is easy to you doesn't mean it's easy to others. You're essentially asking people to ignore every biological instinct they have, and years of specific social conditioning, in the interest of politeness. Clearly not being an [wagon] deliberately is a good thing, but it's not like you're asking someone to call you by a nickname.