It's difficult to figure out what it considers to be toxic, but so far it seems to be cursing. The medium setting also hid a comment which was an opinion, albeit a bit harsh. Luckily you can mark comments as "shouldn't be hidden". I disagree with other reviews on here that are scared of this extension. It's not censoring either, that's just pushing it. It's just a way to silence the noise. Sometimes when I'm researching something I don't want to get dragged into discussions and people yelling at each other. This extension would be perfect for that. One very important point I'd like to make though is that it should stay in this specific form. Don't quietly hide comments, the dots that replace the comments currently are perfect. As long as it is opt-in and can be tweaked I think this extension is a great idea. I do feel there's something to be said about being allowed to post toxic comments yourself even though the filter is turned on. It hides your own comment when toxic (I tested it. Obviously deleted my hateful comment after) but I don't know if that's enough.
I don't think this is the right way to go about the problem. I don't know the solution, but blocking it out all together from a third party is not a lasting and productive solution.
I sometimes deserve some mean stuff, both digital and offline. Everybody does and everybody has to learn to deal with it. Nevertheless, online "toxicity" has a different nature, so it should be an open conversation. I don't think that it's a perfect solution, I don't think that it's even close but let's give it a shot and see...