People about Cosplay...
Absolutely! Just not in the way your potentially-leading question could be interpreted to imply.
Wikipedia says that “cosplay” broadly applies to any costumed role-playing in venues apart from the stage. Therefore, it’s only the growing and disturbing layman’s trend of equating “cosplay” with “manga/Japanese” which makes it appear there’s a problem. My generation was cosplaying before the term was coined (c.1984), and thus we “costumed” at conventions as characters from Star Trek, Star Wars, Ghostbusters, Doctor Who, Marvel and DC comics, etc., none of which are anime or in any other way Japanese in culture. Even if some were, most other characters equally originated from different countries and cultures, so on the surface the answer would appear to be “no”.
Now, is cosplay appropriation of any kind? It’s actually nothing but! By definition, cosplay is of a previously-established character from a previously-established distributed media venue (TV, film, books, etc.). You’re always cosplaying a character which someone else invented, or at least basing in on one (crossplayers, etc.). You’re not asking the creator of said character to do so, so yes, you’re appropriating it. But it’s an appropriation of trademark or license issues, not of culture… all cultures are potentially fair game for it.
Finally, cosplay itself has matured and spread enough that Wikipedia already classifies it as a “subculture”, which I suspect is a conservative definition if you’ve ever been to a comic-con.
So: cosplay is, in the end, a “culture” based on “appropriation”. If we concede that this encompasses any culture and appropriation, then your answer is a resounding and unabashed “yes”.
No, it is perfectly normal to buy a cosplay costume. Even professional cosplayers buy or get the costume made from someone else. However, making your own costume has a different thrill to it.
What is important though, is how you carry the costume and how much fun you’re having while cosplaying.
As for “devaluing someone’s participation” goes, some may feel that your cosplay is superior to them, when they took more efforts. However, it is not supposed to be that way as these things are done for fun.
Ancient peoples dressed up as animals and gods. They dressed up as powerful characters of myth and reenacted stories that were important to them.
Modern people do the same. On Halloween, people dress as archetypes of many kinds, At Christmas, you see people dressed as Santa Claus in the US, reminding us to be kind to others, even if we don’t put change in this particular pot.
Once, I was in an Indian restaurant and as I waited to be seated, I looked at pictures of a party at the restaurant. They had two people cosplaying Krishna and Radha.
I attend anime/manga gatherings and I know from talking to many, many people about this, that the drive to dress up as characters you love comes from wanting to participate more deeply in the narrative.
At Renaissance Faires, I was quite often told by people “this is my real self,” as opposed to the normal worker bee they were during the week.
And then there is cosplay as a sales technique. Booth babes are hired at tech and industry shows because getting a dorky guy over to the table takes work. Geeky folks are cynical folks, but a pretty girl will draw many men without working at it. Once they are there, they must of course be engaged and thrilled by the tech, but the hook is the girl. Or in a maid cafe in Tokyo, having someone be kind to you, call you “Master” and do your bidding feels good, even if you’re paying by the hour.
So, why cosplay? To engage with our mythical/narrative roots; to take on skills and powers that we don’t normally have, in the context of ritual – or fun; as a visual hook to drive commerce; to enjoy, for a moment, the thrill of being something else than we are or who we feel that we really are.
We may not all cosplay, but we all play dress up from time to time. Next time you slip into tux or a really nice dress, think about the cosplay you’re engaging in – what are you projecting? What makes this you different than the everyday you? What powers, skills, qualities are you pretending to have?