If you walk down a public street, you might not have a conversation with everyone on the street. But that doesn't mean if the cops ask a random guy if they saw you that they can't say "yes", or the guy you bought a hot dog from, etc...
A surprising number of people trust the police to have good intentions when they're trying to find someone...and you know what, if the cops came to my door and asked if I've seen a guy around the neighborhood with such-and-such description, I'm pretty sure I'd give them a prompt and truthful answer. I suspect most people in late-1700s America would too, no matter what you think the founding fathers might have said.
If you want a telecommunications company that won't give up your info without a warrant, go start one.