That's a given for any clearnet email provider. You'd be an idiot to do anything criminal with a clearnet email account and not use Tor + PGP. They can still get metadata, like the email addresses you were communicating with and the dates / times of the emails, but the NSA probably already has that data. The issue is, some services won't communicate with you when you have a Tormail address, or it might look suspicious if they know what it is. There are use cases for clearnet email providers, and Safe Mail is one of the few that allows you to register over Tor.