Being silenced happens to women and other oppressed peoples. I would say that is happens to minorities, but women are the majority. Strange that.
I made a comment once on another expat's blog, saying that I found a marketing campaign sexist. That led to a mobbing where people that I have actually met- not random strangers- told me that I should get laid to improve my sense of humor. Another person I actually know told me that was not an ad hominem attack and that this advice was not sexist. She was a feminist, she said. She should know.
So I removed these people's blogs from my reader and made a point of not seeing them again. I don't have problems with disagreement: I do have problems with people who flash mob and escalate.