How people form their opinions matters. The bottom-line-writing process, after all, is not "how do you defend your conclusions?" but "how did you form your conclusions?

In other words, not "what do we hear from X's towards non-X's in arguments?" but "on what basis do people acquire X views in the first place?" (We do not live in a world where these are equivalent. If they were, then all rationalists would automatically become perfectly persuasive speakers — which is not the case.)

When I think of a person becoming a feminist, I think of a person who had a lot of previous personal experiences with gender relations, different treatment of men and women, etc.; who is then exposed to feminist ideas, and finds that these ideas offer ways to describe or explain experiences they could not relate (or explain the importance or value of) in non-feminist ways of talking about (e.g.) upbringing, relationships, workplaces, etc.

When I think of a person becoming a Holocaust denier ... well ... I don't really have much of a model of that, since I've never observed the process — but I don't get the sense that it has a lot to do with previous personal experiences. Rather, it might have to do with them having read some Holocaust anecdotes and history (in school) for which they are now accepting the explanation "these anecdotes were written by a fraudulent conspiracy" rather than "these anecdotes are pretty much accurate". I'm not sure what the motivation is, though, if it isn't either ① politics, or ② the usual "I know a secret" found in a lot of conspiracy theory.

I can't in 30 seconds find a better representative of feminism than jezebel

There's a list of introductory feminism sources in the Feminism 101 article at Geek Feminism Wiki.