Even if you can't spend the time to check, what is so hard about just correcting yourself when someone asks you to use their preferred pronouns?

Pure stubborn pigheadedness. Easier to put your back up and complain about other people than to admit you made a mistake.

And fucking no "they/them" isn't an easy way out post-correcton.

I mean, it would legitimately be nice to use a set of gender neutral pronouns when you're in a big online space where the individuals you're talking to are virtually strangers. I thought that was kinda where the whole Xe/Xer was going, but people got nasty and vulgar with that as well. So it seems like we're strictly adhering to Rule 30 and assuming everyone is a dude unless tits are clearly on display.