People go to chatroulette to talk to another random person, not to be broadcast to the whole world. It's not any more ironic than "rain on your wedding day".

But people on chatroulette are broadcast to the whole world, just one person at a time.

I know that sounds cheeky, but chatroulette users are already taking chances with privacy, they're letting some random stranger view into their lives. Maybe they're not expecting a record of their interaction to be made, but even that isn't that good of an expectation considering chatroulette videos started showing up on YouTube almost as soon as chatroulette started.