I do feel the raiding community is dying.
I'm a raider and I enjoyed BCOB, SCOB, SCOB Savage and FCOB back in the day. Cleared them without nerfs of any sorts, except for T5 since I didn't have a static back in the day. (This is not my main). Hyperion was full of competitive FCs, committed players, statics that worked as a team. Bunch of LS where you could pick up players that can manage and do the content without major issues. People enjoyed raiding because these 3 factors you mentioned. I feel that everything is gone now. Most raiders migrated to one single server, which is Gilgamesh. So the raider community got cluttered there, whereas other servers its group is slowly dying. Less and less people put PFs up to clear content together with pugs. It's all about statics missing members, trying to fill spots for weeks (Myself included, still looking for an MT).
People lost the motivation for raiding, and that hurts me, because it's a kind of content that I truly enjoy but almost no one is down for it. I wish I could move to Gilgamesh too, but I appreciate the company of my friends, even though they are all non-raiders.
Attitude wise, I try to reinforce the idea that not all raiders are bad. That they're helpful, that they are patient, that they aren't that one quiet player that rushes through the dungeon using all his party members as a mere object. Humilliating you if you did 300 DPS less as a DPS class while he was in a tanking class. After all, that's the first lesson you learn from raiding: Patience, followed by: people have different learning curves. It's not matter of life or dead if you wipe. Mistakes happen, learn from them. Try to give advice if needed and/or asked. Be polite to your fellow party members, after all you're part of the team and you all work as a whole. Help people. You, as a raider, experienced and somewhat skilled, have the power to help these guys. Don't be cocky, because you're leaving anything but a good impression.
In the end, both sides will attack to each other, since there're rotten eggs lying in every community nest. We can't change some people, we'll find them, that's for sure, but they don't represent the group as a whole. You, as an individual, have the power to understand this simple concept and just avoid generalizations like "all raiders are special snowflakes, elitist and toxic players that want their content away from the casual players" or "non-raiders are casuals that suck at the game and they feel entitled to everything the raiders have without any effort". Such is the magic of the internet, where your face is covered but your mouth, so you can be mean all you want and get away with it. When people fall into dehumanization, we know we have failed as a society.