Powerful Moderators

What is the point of the moderators on the website? I thought it was to remove the racists comments trolls used to make but now it seems they remove a ton of comments. Is there an outline on what the are supposed to do or are they public? Or just an unknown, all-powerful group?

I’ve noticed joke comments on threads that are later removed by mods which is ridiculous. I am worried the mods may be deleting too much in an effort to sanitize the website.