I don't understand...

[Foo01]

... The problem is rude players and players who could be doing a lot better but do not do so out of sheer laziness ...

Stop with the assumotion that they are lazy or rude.

... Also, from my experience, a lot of the time it is the player given the advice that becomes rude...

Advice that is not asked for and comes across as a bossy command is likely get a poor reception. Perhaps the so called advice was rude to them. Rude is subjective.

This is a multiplayer game, and if you choose to purposely play in a way that hinders others, then YOU (not you directly, this is a general statement) are the problem.

Players deliberately causing wipes over and over are trolls. They need to be reported.

"Hinder" is too vague and subjective. Not optimizing is not hindering, because that is dependent on skill level and experience. Don't confuse trolls with players playing in earnest. So if we exclude the trolls from the discussion, then whole notion of "correct rotation" is bogus, different players will play a different style and that is totally ok.

Only the elitist insist on one optimized way and force everyone down that path. And it is the elitists that force the speed runs, because to them that is the only path of "correctness" and obviously to do so you must do the "correct optimized rotations."

.... purposely harming the progress of a run is selfish and inconsiderate ...

Only troll purposely harm the progress. Going slower is not harming the progress. Watching cutscenes for the first time is not being inconsiderate. Taking detours to grab loot is not harming. Not skipping mobs is not being inconsiderate. And not optimizing is not harming nor is it being inconsiderate.

To an elitist such talk blasphemy because everyone must follow their narrow strict path. That is not what any game is about much less a MMO where the whole point is to let people be free to be who their imagination takes them. Some them even want to be trolls, but that is why they get vote kicked, reported, and get to play by themselves.