I'm really confused about this. So Techcrunch is telling companies that if they want coverage, they have to not talk to anyone else? Couldn't they instead just talk to everyone but Techcrunch?
Yes. It's very common for blogs and press outlets to ask for exclusives with a deadline at which it expires (embargo). If you want their coverage, you agree to their terms. Or if you have your act together, you set your terms, pitch it and have back up plans if they don't accept.