It's a cultural thing I suppose.

To me, using something like Duty Finder is entering a sort of social contract in which we attempt to achieve a shared goal (the dungeon/instance). Because we're operating as a group, it falls on each player to, at the very least, put forth a basic understanding of how their role/class operates and carry their share of the "weight" in the party. It's simply the responsible thing to do. This means things like combos/rotations, CD cycling, DPSing when no healing required, etc.

Anything less than this basic game play shows that you have entered the group with the intent of completing the goal without carrying your share of the effort, and therefore you want to leech off the efforts of others. It shows a severe lack of respect both to the other players and their time.

Sometimes there are players who just don't understand something, and that's fine. If they're willing to learn you can instruct them on the issue(s). But often times they're not and will either ignore any advice or actively deride you for giving it. In this case, the mask comes off and they've shown they don't care about you or your time, you're just a vehicle for them to leech off of till the dungeon is over. And we should not be promoting that kind of behavior in the game. It's no less toxic than the toxicity of elitists, but still there are people that will give it a pass for some reason.
but we both know that there is no contract, despite how you imagine it. You're owed nothing by any player, just as they are owed nothing by you. And in that situation you have a few options. You can try to kick them, leave, or try to complete the instance. That is the extent of what you can do. period. end of story. because you cannot control other people.

If you feel that someone else is not putting in "sufficient" effort for you, then the onus is on you to either withdrawal your own effort, or not. I generally have too much pride to do that, but I wouldn't judge anyone who does. I personally was always raised and taught that giving unsolicited advice is rude. Always. And no, they do not owe you any manner of respect for your time. If they do not and that is unacceptable to you, i would again refer you to the few things that you can do in response. I'm simply of the opinion that the unsolicited advisor is the one who is being more rude and more petulant. It is well within your control to use your vast wells of expendable effort to seek a party that is more in line with your expectations. Because to me, that's the crux of the issue. The person imposing their expectations is the advisor, not the lazy/distracted/sub-optimal player. If you have a problem with someone's play, it is your problem and it is on you to either address it by moving yourself into a different situation, pleading your case to the group for a kick, or not.