The issue is that the game does support that kind of attitude through a combination of:
1. Having end-game equipment gated behind tomes that are most easily capped through 'roulettes'
2. Encouraging experienced players to play the same older dungeons over and over, creating a distaste for slow runs
3. Increasing the skill-gap between the good and the bad players
4. Preventing information readily available to properly address concerns
5. Providing no 'rewards' for proper behavior (i.e. killing trash, helping newbies etc.) The only reward is for completion; therefore, the faster completion the better.
6. Having Duty Finder group up with any random person, likely resulting in conflicting playstyles. Which then in turn results in frustration.