agree its saddening how much people want to impose their self-beliefs onto other players. This is not the only case. Regarding this there are good points on both sides why it is beneficial to watch and do stuff over others, however a player should never be bullied into playing the game how others want it to be played. If you want that then use the party finder and make that clear.
Personally i only like playing mmo games if they are fresh, so i can experience the content first hand, the experience feels totally different, like actually using your brain to work through instead of being spoon fed everything. Whats more horrifying is when you join a 'learning party' and people have these expectations, its not really fair for those that enjoy the game just to have fun, even if you are wiping, and having a blast because the you are taken for a treat with each new mechanics.
Personally when new progression content comes out i would love to go inside and not know anything about it, and try to figure it out and work through it with 7 others.
And I never really understand the 'wasting peoples time' arguments. If i join a dungeon im making a conscious decision that they may be players that dont know the dungeons as well, and some 'first timers', because nothing makes me special over them, i feel it would just be selfish of me to dictate that everyon should see a video, and know the fight even though ive done the dungeon 100 times. If i dont like that i can just join with friends/ls/fc people, join or make an experienced party.
A player at the end of the day is entitled to try to work the dungeon for themselves, and enjoy their game, which is in their right to do so. People simply want to exercise that aspect of the game. Its like calling someone an idiot or they are doing it wrong cause they choose to walk to the shops instead of using transport, or if someone chooses to not use a calculator while solving a math problem because they want that extra mental stretch.
At the end game boils down to having fun and people have different goals, if people want to blame others for their lost game time, or how others are wrecking the game for them, then that is pretty lame and irresponsible, cause that is determined by you not others. You dont like something the "leave duty" option is always there, i myself have used it many times, for whatever reason, did i leave cause people were horrible? No, for w/e reason whether we didnt share the same ambitions, or i didnt sync with them, or didnt enjoy the experience with them i left, bottom line i didnt want to play with them, where they at fault? no they played how they wanted to play, i played how i wanted to play.