Boardhost says:
The following content is not allowed on your message board or forum:

Racism
Hatred or hate speech

I already posted link from a site that says it's a "derogatory, offensive, and racial/religious slur used to refer to a Muslim."

https://www.onelook.com/?loc=olthes1&w=muzzie

I don't know how that site decided it's derogatory. I don't know how some words become derogatory. I don't know why some people decide to be offended by some words and not be offended other similar words.