Well it’s pretty rare that I see a single-pulling tank, but regardless of anything, my general advice is:
1) If someone isn’t being mean, then there’s no reason to be upset. They haven’t actually done anything wrong.
2) You don’t really have a right to criticize someone playing a role you didn’t queue as. If you wanted that role to play a certain way, you should have queued as that yourself.
3) It’s not the tank’s fault healer gameplay is designed the way it is. Blame SE if you’re bored, not the tank. They didn’t make you player healer, you chose to.
4) Remember you’re the one who chose to queue with randoms. Nobody made you do that, that was your choice to accept getting literally any possible kind of player in this game. Maybe you should learn to accept the potential outcomes of your decisions.