Have you ever tried savage? There’s plenty of mechanics where if any one job makes a mistake, it’s a wipe and the run is ruined. Also you won’t beat enrage if one dps dies and stays dead, unless the rest of the party can cover that dps, which is possible but isn’t that frequent, because everyone else has to be bang on their rotation and (to a certain extent have the gear) to cover the dps loss.

If the tanks die on first mechanic it’s a wipe to, so it’s not exclusive to healers, the dps simply can’t pick up the tanking and carry on the fight.

You forget there are plenty of bad tanks who don’t use CDS correctly, die to tank busters. don’t position the boss correctly (confusing the party positions and causing wipes this way) and don’t have the dps to beat enrages when dps is lacking from the dps job side. Extra dps from the tank can be the difference between enrage and a clear.

And from the dps side? If they can’t do their rotation and optimise, the party will struggle to beat enrage. If they stand in aoes and are always dying, the group won’t beat enrage, etc etc.

If the healers are expected to have a higher standard, then why not the other roles to? Healers are only one part of the machine.

Bad players are not just exclusive to healers.