I'm honestly not sure where the idea that people who do Dapper Day and other events, or blog about something they're passionate about are somehow trying to be superior. They may not be your cup of tea (I don't watch vlogs myself), but I've never gotten an "elitist" vibe from them. Anyone can participate in dress-up days if they choose. I'm not an AP, and I participated in Dapper Day in 2016. I certainly wasn't sitting on my smug a**, congratulating myself on being so superior to the "commonfolk." As far as I could tell, everyone was just doing their own thing, whether they were wearing three-piece suits or jeans and t-shirts. Nobody cares so much about strangers that they'd choose their Disneyland outfit or make a video solely to irritate them or make them feel inferior.
As for dressing up in general, I think there is a great deal of misunderstanding about the reasons people dress up, at Disneyland or anywhere else. I'm a grown adult who has cosplayed for more than a decade. For me, and most people I've interacted with, it's not about "LOOK AT MEEEE! I must be the center of attention!!!!"" It's about creating something, whether it be from scratch or an outfit you thoughtfully put together. It's amazing to see the creative ways people portray a character or an era. Moreover, it's something many people do with their friends. I know a group who hand-makes their Dapper Day outfits every year in between working their day jobs and managing their families. And then they get to go to the park and have fun together and enjoy wearing these outfits that they labored so hard at making. And heck yes, when you've worked hard to create a piece, it's great when someone compliments you on it. In this case, it's not about "LOOK AT MEEEEE!!!11" It's about, "Hey, look at this cool thing I made." But getting attention isn't the REASON most of us do it. We do it because we enjoy it.