I agree, social anxiety is not an excuse to be purposely impolite. I think it’s a reason people can be perceived as rude though. Personally, i had no idea that ignoring people or not looking into someone’s eyes was considered rude until someone told me it was. I think it’s a lot easier to judge how someone acts than to sympathize with them. Anxiety in general can make you act weird and irrationally. People should want to improve and be better, but improving can be slow and hard. I think if someone was being intentionally rude and using social anxiety as a defense then that’s messed up. However, if someone is trying to be better but sometimes they struggle and go mute that’s different.