I hate to say it, but good. What you are saying is that anyone spending money producing and distributing a show has no right to make additional income from it with episode DVD sales. Clips, within reason, but there are reasons not to also.
I see it from the other side. Hopefully this summer, I will be releasing some low volume DVDs to the consumer market. Just what I want is someone killing the little I could make by posting major chunks of it on Youtube. In fact, Youtube's posting agreement gives them FULL rights to anything posted there. That money I make will go to making other producations and make it worth my while to spend hundreds of hours on filming, editing, and all the post-production work it will take to distribute it. I will not post there as it gives them the right to put it on a DVD and sell it. Not for me. And, if I have synchronization and mechanical rights to music in the clip, that would be more money and possibly a change in my agreement with the music company to post it (synch and mech rights are the most freakingly annoying and hard things to do as it takes usually 2-3 parties and a minimum of 8 weeks just to get going - I had to get both Sony's and HBO's license and send them checks to use a hummed "Band of Brothers" in a video.) So, somebody posting content from a show, could violate the show's licensing agreements and "gives" the show to Youtube. They cannot do that without permission.
That said, it is in the best interest of the shows with the "funny" to post some of those clips on a service or at their site for sales. Good teasers are good marketing.
And I really like Youtube. I think the music industry needs to post every music video they have up there. MTV sure won't play them. And sorry RIAA, it really does mean CD sales will increase (morons.)