I think it really depends upon who is saying the stupid things & when. Her being a teacher, yes she does need to watch what she ways & when. If any student hears her say unkind things (even in jest) it can make students think that it's okay for them to do the same...and they'd be right.
I recently worked with a woman who thought it was okay to call everyone "sweetie" or "sweetheart" and on top of that she had ZERO
clue about personal space! SOOO UNCOMFORTABLE!
Fact is, one day after I'd just gotten on the sales floor she smacked me on the behind & made a comment! I was really taken aback! She actually blamed me for being in a rotten mood!!!
She apologized to me the next day, mostly because I filed a complaint with the store manager. A little while later she was talking to the asst. man. about apologizing to me & why. Instead of just TELLING him what she did, she smacked HIM on the behind! Yup, YOU CANNOT FIX STUPID!!!
If it's someone who really matters to me, I let them know that they should engage their brain before their mouth. Not saying I'm perfect. If someone is really that freakin' stupid, I let them sink their own ship & have very, very little to do with them. People do judge you by who you associate with. Lastly, there is a big difference between saying stupid, inconsiderate things & being just flat out RUDE. RUDE is a big NO in my book.