Your entire debate isn't about time. Time is just an detrimental effect regarding the root cause.
The root cause is effort. It's offensive to a lot of players watching someone AFK in a dungeon when they can do more. If they try and fail and own it, people understand and adapt.
The issue has, and always will be some moron wants to watch netflix while running Totorak for the 663rd time, forcing me to have to play even harder to make up for his apathy.
That's toxic behavior.
The fact that the run takes 23 mins or 15 minutes is irrelevant. We're not mad it took longer, we're mad that you had no respect to try and help out to speed it up. This is not about going for speed runs. This is about pushing more than 1-2 buttons over and over.
This is why I'm actually have fun with Blade and Soul. I can solo some group content and it provides a significant challenge, if I want to do it easier, I just group up. I always put forth the most effort I can in group content.