It's not about saving you time. It's about saving other people's time. When you do a dungeon for the first time, do you tell people you are new? Do you read any explanations they give or do you tell them to stuff it because you want to do it fresh? I'm guessing, or at least I hope, you don't. If that's the case, what is the difference between watching a video and reading a semi comprehensive text-dump? Expecting others to spend large amounts of time so you can "experience the game as it was meant to be" is far more selfish in my opinion. And do note I'm only talking about tougher end game content, everything up to maybe Garuda/Titan HM can be learned in a single attempt without much issue.
There are undoubtedly some jerks, and I'd never condone berating someone for any reason, but joining a group and expecting everyone to play around you is pretty selfish too. We can argue all day whether or not DF groups have unfair expectations, but we can't argue those expectations exist. Why waste a lot of time fighting that? It's like the whole Bone Dragon tanking spot. I think people who tank north are heretics and must be stopped, but I'm not going to fight it mid-instance because I don't want to waste a bunch of other people's time.
Premades (PF/FC/whatever)are generally the far better route for learning runs. Again you can argue that is unfair but it's undeniably the current environment.
I didn't look at videos or read when I learned and figured things out with everyone else. It's selfish for me to expect then that people who weren't playing at launch or are slower at leveling would need to do research to play the game. Explaining in game is different to me than looking at some wiki. It is social and it is within the game. It is not extracurricular work as tutorials and videos are.
If it's DF I expect all sorts of people to join and I do not put unrealistic expectations on them to research. It's selfish for me to expect extra work from people just so I can get through stuff faster. Their experience is more important than my saved time in the endless end game gear grind.
If I don't have patience for new people then I need to go look for like-minded individuals to form a static group or make it clear what I want in PF so people can avoid me if they want to just play the game rather than satisfy my unfair expectations.
Whenever they add new content and I go do it, I'll continue as I always have. I will play the game instead of researching and watching videos. I have zero tolerance for jerks who value their time above everyone else. You can say I am selfish in that but if I have to choose between:
1) being selfish by believing everyone deserves to play the game without harassment or,
2) being selfish by believing my time is more important than your experience,
I'll choose the first option.