It's not a simple thing, but in reality, the only "wrong" thing here is how he said it and that he did do so at the end, not at the beginning.
However, it seem to me like the party could have meant that it's fine with them at that time, aka. at the boss that you got locked out of. Not necessarily a free pass to watch the cutscenes from then on freely. They just didn't want to say anything afterwards for one reason or another.
You have to understand something too. "The way it's meant to be played" is a horribly wrong argument here. For starters, there is an option to automatically skip watched cutscenes, so it is very much "how it's meant to be played" to skip the cutscenes. Then there is the option of watching these cutscenes in particular at the inn. I know that it is a bit different, I myself have watched all the cutscenes till Garuda "live". However, that was the first long cutscene and I genuinely felt bad for holding back the party like that (as a healer), so I apologized and it so happened that someone told me about the inn...something I had no idea about. Let's ignore the fact he said it in an outburst, cause it was still valuable information.
After that, I do not watch most cutscenes in dungeons. If I can watch them AND not waste the time of others, why not skip them?! Respect is a mutual thing. I'm not more important than others, and neither is the reverse true. If I couldn't watch the cutscenes, I would watch them. But I can do that as much as I want. I can redo the dungeon later on to watch them "live". So though I won't say anything bout people watching the short cutscenes in normal dungeons, I will tell people in Praetorium and Castle Meridianum, after the first cutscene, that they may want to skip the cutscenes and watch them at the inn later since the party is unlikely to wait for them. Without name calling and all that, of course. If they will still watch cutscenes...well. They still won't get to play it "how it's meant to be played", since they won't...well...play anything at all. Just watch the cutscenes one after another. It's just too much of a pain to get worked over people that don't show respect to the time of others, just like it is too much of a pain to get worked over people that do not respect others.
Now, don't get me wrong. I'm not saying that you were "rude", or rather, I can understand that you did not mean to be rude. But showing disregard for the time of another...is...in fact...rude. Consider this. If a cashier at a shop you go to kept talking with the client in front of you for twenty minutes, without ever finishing scanning her things till then, cause it was her friend or whatever, would you feel angered?! Very much so, because your time was wasted, no questions asked. It would be rude to you. You however did this very thing. After all, the friend of that cashier also did "spend money", just like you. So she had the "right" to get a "bonus" from her friend, right?! Remember, these things never go one way.
PS: You completely misunderstand what a roulette is for. It is very much "farming" option that is meant to provide farmers with bonuses for helping fill parties in need...or just other farmers. To even use a roulette, you need to finish the dungeons contained within. It goes without saying that in that case, EVERYONE using the roulette FINISHED the dungeon at least once. It is the exact opposite. If you do not want to be with people to farm this dungeon, then don't use the duty finder but party finder. Of course, you'll be waiting then for hours before it fills up, cause most people have no reason whatsoever to run them normally. That's what roulette is meant to fix, so that you would actually have who to run it with without knowing people that could help you.