It depends on how things have shaped up over time. I have read before that pg is ok with the use of downvotes to indicate disagreement or annoyance without follow up comments. Here's that comment from nearly nine years ago: [1]
> pg 3246 days ago | on: PG on trolls
> I think it's ok to use the up and down arrows to express agreement. Obviously the uparrows aren't only for applauding politeness, so it seems reasonable that the downarrows aren't only for booing rudeness.
> It only becomes abuse when people resort to karma bombing: downvoting a lot of comments by one user without reading them in order to subtract maximum karma. Fortunately we now have several levels of software to protect against that.
seems like there needs to be one down arrow for simply disagreeing with the comment, and another clickable entity for flagging that comment as inapproproriate/impolite/notconstructive/toxic, etc.
"Hey, let's penalize that person for participating!"