Simple ways to participate in the anti western cosplayers movement :
1. Get in the anti western cosplayers circles

2. Add more likes

3. Use the hashtag #AntiWesternCosplayers
4. Take the poll "why do you hate western cosplayers?

Why do you hate western cosplayers?

Search : For example "Cosplay of the month" to see evidences of why only us Asians can Cosplay

The best response to any racist westerners who claim our Anime characters in our Anime with western story setting as of being based on them

This is a more detailed explanations of http://antiwesterncosplayers.blogspot.com/2015/11/the-best-response-to-show-how-retarded.html

The best responses when you see any of the racist westerners who claim that our Anime characters from our Anime with western story setting as of being based on those westerners is by asking them about what race are the peoples in this movie trailer
If they answer them as westerners then that just proves that they are retarded because any sane peoples will answer them as Asian. If they answer them as Asian then that also proves that they are retarded because of the logic they use are just retarded logic, retarded logic because a story setting will not automatically reflected on the characters appearance. For example there are many movies where the story setting are outside of earth but the cast or the characters are still look like typical human. For a more better example is the video above where you can see the appearance of the cast is still the same typical Asian appearance when the story setting of the movie are outside of Asia.

As for the actual reason why we Asians make a few of our Anime with western story setting are purely for story purpose just like how westerners make a few of their movies with Asia story setting.