Privacy

This is just the silly libertarian argument. No sane person believes that all crime will disappear because of X law. It's that easily accessible encryption makes it harder to obtain evidence of criminal activity in increasingly many cases.

"Driving people underground", is actually good for law enforcement. Believe me, criminals want to do it in the open it's so much easier. The fact that their is a barrier is itself a deterrent. Look at economic studies of drug abuse, as laws are more lax, drugs become cheaper and usage increases. This is true with essentially everything, as capital costs ( i.e effort) decreases the product/service becomes more widespread.