I know the last time I played with Whonix it was http, so I think you're right that it's a recent change.

For tails: https://tails.thecthulhu.com/. It appears to be the same server behind http://dl.amnesia.boum.org/ based on the TLS cert.

The situation is messy to actually use https for all of these projects, but I think the issue now is organization rather than overhead.