The attention and skill is needed on behalf of the healer, not the warrior, which is where the problem stems from. If you could be as good, if not better, than a PLD by being skilled there wouldn't be so much fuss over it. A good tank is ever conscious of their team and even more so their healer, as they are the lifeline of the group. Being a warrior means you're putting extra workload on someone else, who is also doing most of the work anyway.
If said player is good at healing and triage, there's no problem. When presented with an alternative that it easier most players would take it, especially in a group environment where you want as little to go wrong as possible.
It will be melee complaining about lag and being unable to hit anyone while BLMs run around spamming Icela-err, Scathe.
