I suspect it's very similar for other leftists. They get downvoted, downvote others, and it's a perpetual cycle. For others it's potential habitual, for others because they're just passing through and use the button as a disagree button.
And that's largely what such buttons are used for. Not anger buttons, but disagree buttons.
So why do you get off on the idea of causing your fellow Americans anger?
Passing by an area just to downvote, that's something angry people do. Normal people don't visit subs for things they dislike just to downvote them. I have no intention of visiting any socialists subs.
Most people don't look at all posts, they only look at subs they're subscribed to. Anger is what motivates people to go to subs they have no interest in just to downvote.