It's the easiest way to establish a collaborative video feed without forcing everyone to sign up to a new service. It's a low tech solution, but it works fine for the time being.
Basically, if you want to make a quick comment on the video, point out that there's a follow-up or refer people to response videos, you can do that in the same thread. If you want to discuss the content of the video in any more meaningful matter, that belongs to the debate boards.
The Wiki wouldn't really work for this. We don't want to be arbiters of what is "best".
To be blunt - that section of the forum is probably not for you. It's unlikely to interest you. And that's fine.
As for anti-FE videos - I'm not sure if we've reached a formal agreement on that. My suggestion would be that these, again, are better placed in the debate boards. Posting them in the Media board does not serve the Society's goal of documenting and popularising FET, but rather its goal of offering a discussion space for free thinkers. Hopefully this makes sense.