RPGMemes

His channel is in the screenshot. As I said in the comment you're replying to, he has explored other TTRPGs on that channel, you can check it yourself. Personally I think he has a lot of great general GM advice and does a service by making this hobby seem fun and accessible.

Just because someone's favorite TTRPG is d&d and they make content about it, does not mean they are wronging the broader TTRPG community. If your favorite system doesn't get enough attention in your opinion, take the initiative to show others why it's great rather than demanding someone else do it for you. No one is obligated to pander to you specifically.

Personally, I have a huge collection of RPGs and I enjoy a lot of indie titles more than the big names and I like to talk about them when the opportunity arises. Never had to bash anyone else or their favorite game to do it.