Be unkind is not a fault in itself. Is not like people post on socials only to have nice, polite and constructive discussion. Lots people share their guts-feelings in the comments. You can be open-minded enough and willing to have a confrontation, but at the same time not feeling too much “gentle” about it. Sometime people are simply pissed ( the news helps a lot for that) and want to let it out. Sometimes some specific arguments rub them the wrong way. Sometimes they are trolls who do that for the gag. Sometimes they’re just plain assholes. You choose when and how interact. Where there’s margin for a cilvil confron, discuss. Where there isn’t, ignore.