People about Cosplay...
I think it is just fashion modeling in disguise. (pun intended)
Overall it is a harmless fun. As a creator (artist or writer) there is no greater honor than someone loving your show so much they would dress as your character and even try to be like them. Even against the possible ridicule.
Playing pretend can be fun. And it’s something everyone even families can engage.
But if you look at the most famous and successful cosplayers (as in Twitter famous) they are either:
A) People that could be modeling in mainstream modeling agencies.
This one is the category that gives more envy and disappointment to your average cosplayers. Of course they will get more attention even if your costume is more “comic/book” accurate or well done.
Like I said, cosplaying is basically fashion modeling. They look amazing and it’s nice to see models having a nerdy side.
B) People with awesome disguises that resemble the original show or movie.
In this category you’re judged by your amazing sewing skills.
So for being ultra famous you need to be one of those categories. But if not it’s just harmless fun you do with friends.
Think of it as early Halloween.
Sadly as a lawyer it isn’t professional for me to do this. But I respect people that do.
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.
To answer your main questions, No and No. Cosplay is supposed to be about inclusiveness, fun, and showing your love for a character.
That being said, as with any group of people, there will be jerks on both sides. There will be those that make their costumes and look down on those that buy them, and vice versa. Jerks can be found at all levels of cosplay, just like regular society. And just like regular society, you have the choice to ignore the jerks and go your own way.
If you are happy with your cosplay, not competing in a 100% bought cosplay and are having fun, that really is all that matters.
People who make their cosplays receive just as many nasty comments and critiques as those that buy them by the way.