There is a full bot mode. And widow and hanzo are perfectly fine on attack in most situations. There are more and less favorable maps, but the hero themself is not the problem
Depends a lot on team composition and player skill, but he is mostly right.
Sometimes you just need bodies on the point and widow/hanzo pretty much collapse when focused.
Now, if they are a really good shot and move quickly and position themselves well, THEN we are talkin'.