It's a game, there nothing to be mad, but people can't bear speedrun, or can't bear no doing speedruns.
At least both tank and healer need to be ok with speedruns, if it's not the case for both, why doing it...
The problem occur when a player can't listen to others.
It's a problem for the dgn (when someone is not ready for speedruns), for the raid (it's harder content so when people don't read some advices or don't read the chat)... even for the pvp (when players play solo... in a mmo game, and only care about killing someone by chasing him and get killed instead).
Don't play solo, and listen to the others, it's a mmorpg, not a solo game...damn
Also i am doing speedruns when i tank, but i rarely have problem, also i never do low level dgn in speedrun, your gear is synch, so it would be too hard for the healer, and when i am doing speedruns, i never got the problem recently, but i remember in brayflox HM, when we wipe once too easy, i always tell to the group i pull less, cause everyone don't have the same level, gear, ect...
I still doing that.