I can kind of sympathize.Some people are just too centred on combat and don't consider that there are other styles of play. I got roasted when I created a character in 4e that was a skill monkey, almost impossible for an opponent to lock down, and made to make the life of a single opponent (DM) hell. It was a 4e Warlock/Bard multi. "You aren't doing enough damage!!!!"
D&D as commonly played is pretty combat focused. And the way you win in combat is by getting your opponent's hp down to 0 (or in 4e, getting them down to half and then Intimidating them – I believe that was a thing, right?). There's definitely something to be said for crowd control, but that's either using one character's actions to negate the actions of a stronger opponent, or using a single action to render one or more opponents irrelevant for a few rounds and letting you focus on a smaller number (a four-on-three fight followed by a four-on-one fight is a lot easier than a four-on-four fight). But if you need to dedicate yourself to sandbagging a single opponent, that's essentially taking both yourself and that foe out of the equation, and then leaving it to the rest of your party to deal with (after they've expended encounter resources in dealing with the rest of the enemies). And 4e is kind of known for having sloggish combats to begin with, so things making combat take longer can be unpopular.