Pretty much. I main Ramattra; I can put up a barrier to help the team through a chokepoint, put down a slowing field that can maybe catch a flanker or dive tank, and make myself a big, tanky target by holding Block in Nemesis Form; but really, for the most part, the best defense is a good offense. The average Tank’s kit, in large part, just isn’t built to block damage; it’s to make yourself a big target, annoy the enemy team, and potentially kill them if they ignore you.
Like, what defensive tools does Reinhardt have? His barrier… that’s it. Everything else is built for killing.