I'd argue commercial platforms like reddit attract toxicity because that's what keeps people engaged. There have actually studies been done on the subject of how Facebook directly encouraged that because being angry kept people scrolling. But when you take the commercial interest out of the picture, there's absolutely nothing wrong with people having disagreements and debate because that's how we learn things. Having your views challenged is not a bad thing if it's done in a constructive fashion. You learn different points of view, and to put yourself in the shoes of other people which broadens your perspective. Forums where you can't have disagreement often turn into echo chambers which isn't really a healthy thing.