The article cited by Oui below says:

Legal experts reply that not using preferred pronouns does not constitute hate speech, so Peterson's objection that his individual freedom of speech was being restricted by Bill C-16  was ill-founded. More threateningly for Peterson, the Ontario Human Rights Commission does say that refusing to refer to a trans person by a personal pronoun that matches their gender identity will likely be discrimination when it takes place in employment, housing and services like education.

So it required the expert opinion to determine the misrepresentation. Even so, his new federal duty as a professor apparently overrides his human or academic freedom of expression. So he was taking a real stance.

P.S. Peterson's own take on his Amsterdam gig.