Firstly, there's often a large mob of them. It's hard to punish 1000 people all contributing a little to the cancel attempt. Secondly, the people who disagree

Firstly, there's often a large mob of them. It's hard to punish 1000 people all contributing a little to the cancel attempt. Secondly, the people who disagree and would like to see some pushback don't want to get mobbed themselves, and so they self-censor instead.