They removed them from the allowed guesses list, or the possible answers list? I might be convinced about removing them from the possible answers, but the allowed guesses should be basically all possible English 5-letter words. Even if they make some argument about kids typing rude words in a classroom activity, well, kids are going to do that anyway...

Removed from the allowed guesses. If you guess "slave" and hit enter you'll receive an error.

I suppose they're both vulgar, but one difference is that "pussy" has a derogatory use that "boner" doesn't have.

Perhaps, but it also has an entirely innocent use that boner doesn’t. At least here in the UK it’s pretty common to use “pussy” to refer to a cat.

Pussy and boner both have innocent uses. A pussy is a cat, a boner is a silly mistake.

It seems inconsistent that dick (which can refer to a penis, a jerk, or a Richard) is still allowed, if they're worried about derogatory meanings.

Quick edit: DICKS is allowed, DICK is only 4 letters

My wife was returning something from the store Dicks. She needed the receipt and knew it had been emailed to me. A quick check and I didn’t see any such email.

So in all seriousness, while I’m at work on a open floor plain facing computer she asked me to search my spam folder for Dicks.

They notably did not remove CUNTS.

"Boner" can also mean a tremendous mistake -- negative connotation, but neither a slur nor a genitalia reference.

Which makes it distinct from a pussycat how?