There are all kinds of good reasons for folks to get permission before posting videos - one of which is that not everything is in the public domain, and we might need to know who the author or composer of a song is in order to get permissions. Aside from that, some folks who make their living doing this, or at least do this semi-professionally, need to have a say in what gets put out in public.

Remember it's not "just us" watching videos - it's whoever that video gets sent to, or anyone who stumbles into it on YouTube.

Dan