You do have to keep in mind that Calacanis and YC are to some extent in competition, so it's not like he has no stake in making YC look bad and 'warning' potential YC applicants off like this means they'll have to go elsewhere.
You know Open Angel Forum has funded YC startups, as have I personally. I love TechStars and YCombinator because they produce quality startups that I can potentially invest in, partner with or have on This Week in Startups.
There is nothing competitie between YC and JMC I can think of.
But it seems kind of weird to see you warn start-ups off from sharing their stuff with facebook through their YC hookup. After all, if the plan of this 'cooperation' would be such a negative for YC funded start-ups I would think that YC would pull out of such a cooperation in a heartbeat. It's not like they're stupid.
Give them the benefit of the doubt and see how it develops.
After all the risk to the YC reputation is considerable so you can take it as read that they've thought this through.
Don't you think that their association with YC would protect them to some extent from trickery like this? After all, the collaboration with YC is widely published and it would get significant press as well as close a bunch of doors if he did something like that I would imagine?
All the other 'zucks' notwithstanding there has yet to be a clear cut case of fraud to come out of all this and I can't imagine YC et al would stand by idly if this happened to one of their investments.