I actually changed my mind, yes while that is a good idea. I am gay and as for a start to making debate/discussion videos I wanted to debunk and prove wrong an article against homosexualiy which involves religion and that can get messy. And I would love to do more stuff like that in the future and talk about politics etc. But my channel now is heading more towards comedic route. I don't know if I want to mix that with videos like that. So I'm just thinking about a separate channel to do it on. I don't want to use either to promote the other. I would want to try to keep the two separate. But I'm worried people would find both and then they would start bleeding into each other. Sorry for the long post :/
I'm not sure how much I can really help since I'm still fairly new at learning all of this, but I can say that I currently follow an active channel of a guy who posts videos about anime/games, cosplay and conventions alongside of social justice topics and it works. (He has over 300k subs.) I follow him more for the SJW aspect than the other stuff, but I occasionally watch his other videos too.
If it's just you being you, I don't see why it can't work. That's what I'm trying to do with my channel. Make videos about things and topics I care about with the hopes that people will follow me because they like, not only the content I create, but also me as a person. If people only want to watch my art videos, then they can do that. If they only want to watch my other video series, they can do that. Or both, the option is there.
At the very least, that would help avoid the "people finding both" aspect of your concern. Though if people do, how much of a big deal is that to you, really? You can keep all the comedy on one and the serious topics on the other. If people try to bring over one to the other, you can ignore those comments or tell them that you can discuss it on your other channel as you want to keep them separate. (If they make a big deal out of that idea, they probably weren't worth talking to to begin with, haha.)
I personally think it'd be fine if you did promote the channels, or at least associated them with each other. No one person is all one personality aspect, after all.
The end decision is up to you, of course, in how you want to go about it. I'm not trying to sway you one way or the other, just trying to give you ideas. Hope it helps ^^;