For me it's the combo of cliche + abuse.  Useless to anyone (cliches contain zero information), and actively harmful to any community I'd want to be a part of (abuse drives quality away like a stink bomb.  I already know what crypto twitter looks like, don't need a second one.)

I would really struggle over someone who was insightful but also abusive.  Case by case, I guess.

I was trying to think about what would lead me to downzap someone. My inclination is to start up a conversation when someone posts content I disagree with. I don't think I would downzap anything if the poster (or even other SN users) were willing to engage. 

If someone's just linking to outlets that are regularly caught knowingly lying to their readers/viewers, I might be tempted to downzap.

Undisciplined

That was the road I walked as well.  I think that's well-articulated.  Hopefully your intuitions are close to how it plays out.