It’s not uncommon
People can use mental illness for all kinds of excuses, some think their mental illness means it’s okay for them to act the way they do and it’s not.
It explains why they act the way they do, but they are still fully capable of doing research and being aware of their own actions.
Plus, it’s insulting to other people with the same mental illness who are making legitimate efforts to function socially.
Just because someone has a mental illness doesn’t mean they wont abuse that fact.
Someone once used that excuse to try and get away with some pretty messed up shit in a group chat once.
Also, someone else tried to use their ethnicity to get away with some messed up shit in another group chat once. Needless to say, they were both voted out.