Since you're dealing with a community it's the majority rule factor. All mmos create stories for people to get into. Majority of the people only read a few quests, skip most cut scenes etc. Since we're dealing with other people by being that one person or a few you're being rude and inconsiderate. I understand CS or meant to be watch but since that dungeon is MEANT to be ran multiple times how many times can you watch it? Since it's MEANT to be ran multiple times the majority rule comes in.
So if you get in a group where majority of the people are doing a speed run and you decided to stay and slow everyone up how is that not being rude and inconsiderate? Same for people rushing a group with most of the people watching the cs? Doesn't matter what it's MEANT for it's how the majority of people are using it. Being the one rude self entitled person is what's ruining the community. I'm pretty sure DD wasn't meant to be used the way it is, but since the majority of people are doing that and isn't breaking ToS or anything the devs don't care. And the people killing the lambs are blisted, why? Because majority rules it's only fair.