Presenting a differing opinion from someone else's with an open mind isn't toxicity, it is dialectic. Attacking the person, taunting, harassing, trolling, or bullying them is toxic. I'm all for lively discussions with others bringing different views but people can get toxic here because #1. They take anyone presenting an opinion outside of the norms of the established echo chamber as an affront to the entire community (see the article Roxanne posted in reply #13) and #2. They choose to fight back with personal attacks vs. gathering evidence and presenting counter arguments.
I'm sure that the people mass tweeting to August Ames telling her that she is a disgusting homophobe and that she should take a cyanide pill were thinking that they were just expressing their opinion as well. We all tragically saw how that turned out. That kind of behavior isn't much different than calling someone bullshit, a bitch, or a cuck, or stating over and over again for weeks that the person's opinion's don't matter because they don't really exist: they are a sock puppet (even after several people proved otherwise).
Those people that get the difference and choose to present their arguments in a civil manor, I love having lively discussions with you and, if we ever meet, 1st round is on me. For those of you that don't understand the difference or just choose to spew toxicity for personal fun, I really hope that the August Ames tragedy has shown you that words do matter, even on the anonymous internet. Words have impact and words can be weapons if used maliciously.