I do think this is one of the big hidden problems with upvote/like systems.
Seeing a post you don't like or disagree with on Twitter/Facebook/Reddit with a lot of likes/retweets/upvotes/etc psychologically puts you on the defensive. 10,000 likes on a post you disagree with means you're up against an army of 10,000 people who disagreed with you! So you do what's natural: you fight back, you summon your own army of people (hoping to get a respectable counter-army of likes). This creates a toxic environment and you can see it play out on Twitter: every Democrat-leaning tweet will have its top reply be a Republican-leaning tweet with a counter-point, and every Republican with a Democrat.
Meanwhile, on 4chan or other old-style message board withouts those systems... yeah, it's just some asshole with a stupid opinion. Just ignore them, no need to waste effort engaging.