As a healer, if you have trouble healing a STR tank who is properly using cooldowns then you need to l2p. You are doing something very wrong.
As a healer, if you have a STR tank who is not properly using cooldowns, it's not totally your fault if he dies, even if he says it is. (If you're good, depending on the situation, you can heal through it anyway).
If you have a VIT tank you should tell them why they're wrong.