
One thing I see often online is when two people are arguing, one will start to correct the other's grammar as a way to undermine the person further. That's one reason why I think people can take offense from it, as sometimes a way of being snarky. Probably completely wrong, but I'm trying to post more so stuff it I'm gonna do it. 
Personally I find it helpful as my grammar is atrocious and I seem to have made up my own set of rules?!
I don't usually comment on other's mistakes because of this, and to be honest as long as I understand what the person is saying then I don't really mind any way. Maybe in a public conversation the safest and politest thing would be to do it through /tell instead.

Personally I find it helpful as my grammar is atrocious and I seem to have made up my own set of rules?!
