My first encounter with Peterson was hearing his "lobster theory", which struck me as such pseudoscientific piffle that I've tried to pay him as little attention as possible ever since.

I imagine the reason Peterson elicits such strong reactions is because he presents differently for different audiences. As suggested elsewhere in the comments, "he's built his own persona into this gigantic strawman that looks like an ogre to everybody", luring them into attacking a position he never held so that he can appear calm, wise and reasonable in his rebuttal, and take the role of the poor attacked underdog.

He speaks of "postmodern curtural marxism", yet by his own admission, has never debated a marxist. Like the best controversialists, he picks his fights very carefully, preferring to "debate" with campus teenagers than other "intellectuals".

For those who haven't heard it, his "lobster theory" goes:

1. Lobsters are animals with a hierarchical society

2. Lobsters have a "seratonin based nervous system". Humans also have a "seratonin based nervous system".

3. Therefore, a hierarchical society is natural (and therefore best) for humans.