Some context:
Breivik (Norway) was an early actor in the war on "Cultural Marxism". Peterson's online class is not just wrong, it's inverted reality.
The rise of cultural Marxism/multiculturalism in Western Europe
https://estaticos.elmundo.es/documentos/2011/07/27/manifiesto.pdf
Jordan Peterson wasn't that famous in Europe back then, but if he was, the manifesto would likely mention it.