I really feel guilty seeing this. This is not the first time and the only person doing such stuffs. And i feel guilty because as a moderator of BD community, I/we couldn't teach him/them the norms and etiquette.
Actually the problem is on their education. They are not that much educated. As English is not our first language, we have to learn it from educational institute while they are not getting it. That's why they just throw any kind of comment seeing others comment being upvoted by you or others and thinking same will happen to them.
We tried many time to contact them in discord and make them understand, but we failed to make them understand.