I agree that his mocking and snark about MatthewMatosis's review of DS2 sabotages his own argument. The way he talks and acts in this video makes it seem like he thinks he's better than everyone who disagrees with him and I just couldn't finish watching the video because of that. Not to mention he got a lot of things wrong in the video like the parts you mentioned and the part with the Turtle Knights and people in the comments are rightfully calling him out on stuff like that. It's like he didn't even watch MatthewMatosis's review. So not only is he wrong on things like the parts you mentioned and the Turtle Knights but he's also being smug about something he's wrong about which is the worst.

I even went back to watch some of his videos and he is just constantly mocking and putting down people. If he really is so much better than the people he's arguing against (such as his arguments against the alt-right) then he shouldn't bring himself down to their level. By doing so he has sabotaged his own argument. That's not how you convince anyone to change their positions. No one cares how right you are if you're just gonna be smug and smarmy about it. It's completely counter-productive to changing someone's mind.

Calm, clear, and rational arguments (like MatthewMatosis's review of Dark Souls 2) will always win.