I think it's pretty impossible for occasionally intense reactions not to happen, especially on a therapy forum where most people are interested in discussing feelings and emotional reactions. I personally agree with LT's earlier notion that disagreement and criticism on its own is not a problem, it's more how it's presented. That is a form of art that, IMO, no one practices equally well at all times. That's where tolerance becomes a thing to practice instead.

On chasing away people, I don't know... but I think when that happens, it's usually due to mass reaction to some form of highly repetitive communication style or behavior and the person being chased away not recognizing or acknowledging it. These things happen all the time on forums and other social media but I personally have never seen it happen without a strong reason or pattern. I think it's rare that someone will get turned away just because one or two disagreements or even misguided comments.