is his echochamber so good that he never heard any real argument against his ideology?

Most normies, left or right, have never heard the actual arguments against their globohomo propaganda positions. They've only heard caricatures and strawmen of our arguments and positions. Their positions have never been challenged or questioned, so they and their ideas are incredibly weak, and easily picked apart and rebuked.

This is because race realists, antisemites, White collectivists/nationalists, and Nazis (REEEEEEEEEE!) have largely been censored off of mainstream platforms since the implementation of said mainstream platforms (like Facebook). It's just that the evil has become so blatant, the world has gotten so bad, that even normies are noticing, and giving ear to the voices of the only people who've been proven right, over and over and over. So, the red pills continue, and increasingly accelerate as the current trends continue.

The enemies of globohomo kept getting censored into niche spaces, but as the purity death spiral of globohomo continued, more and more people kept being pushed into those niche spaces, for increasingly small infractions of wrong think, exposing more people to the truth. And then, our numbers got large enough, people became brazen enough (what do we have to lose at this point anyway?), and a few globohomo missteps (like Elon eliminating most of the censorious bastards at Twitter), has allowed the truth to be spoken in mainstream spaces by increasingly large crowds of people who are getting increasingly and rightfully pissed at how we've been constantly screwed over, even by our purported "allies".