It is also a great boon to privacy. We believe in keeping the government in check. Unlimited government is an unlimited disaster.
Privacy is important — for keeping government in check, amongst other things.
However, I keep hearing how lax Canadian security is a threat to the U.S. (and there are a lot of valid concerns) — yet, we've got much tighter security regarding telecommunications. It just doesn't quite add up.
Phone records for land lines, and registered cell phones can be gotten by subpoena (for a good reason, presumably) — yet, anyone wanting to make unlimited anonymous calls just has to visit the local 7-11 and buy a disposable phone. To be consistent, it should be all or none.