Tails is ridiculously well known; if something was bad in it, it would be big news.
Debian, which is much better known and in much wider circulation than Tails generated weak SSH keys for two years. Yes, it was indeed very big news. When it was found. After two years.
Oh, and tin-foil-hat on: Do we know (actually know-know, not just assume, think, trust) that the weakness wasn't planted there?
Also, how do you know that Tor and Tails aren't infiltrated by the enemy (for any value of "enemy")?