The focus should be on opposing suppression and ensuring freedom of speech, not on the psychology of those attacked. Not everyone who speaks out is attacked. Only some are. There are all sorts of factors involved. For suppression to occur, someone must take action against the dissenter.
Personalities play a role.
There are some regularities in suppression. The actions which can be called suppression most often are implemented by people in positions of power in organisations or associations. It is helpful to assume that those who are responsible for suppression are sincere. They really believe that the dissident is incompetent, unauthorised or whatever, and that their own behaviour is quite justified. To call something suppression is to challenge the explanations given by those in power.