I love how this argument keeps being used.

The problem with it is that this site is run fairly similarly to a museum.

If a museum had an exhibit on ancient Egyptian culture, would you call them racist for not including ancient Chinese or ancient Greek culture in the exhibit?

No, because it doesn't belong there. It isn't a culture exhibit. It's an EGYPTIAN culture exhibit. Anything else is out of place, and would make the exhibit meaningless.

The same is true for here. This place is run like a Japanese art exhibit. Art from anywhere else does not belong, and makes the site meaningless. The entire point of the site is Japanese art. Period. That's all there is to it. It isn't a porn site, despite approximately 1/3 of its posts being erotic in nature (and yes, this was approximated with actual statistics, it IS only about 1/3 of the site). It isn't an art site like Pixiv or DeviantArt where people upload their own art to share with the world.

It's a website for Japanese art. That's all there is to it. Expecting anything more out of it, when it's stated in various places on the site that it's a site for Japanese art and nothing more, is ludicrous.

It is also not a site for your entertainment. Sure, you can feel free to entertain yourself here. Enjoy the pictures all you want. This is also possible in museums, as well. However, just like a museum, the actual main purpose of this place is to serve as a collection of culture. Specifically, Japanese culture. Therefore, even if art by non-Japanese artists is good, it doesn't belong here. To that point, it's similar to if you were to try to put da Vinci works in a Michelangelo exhibit. They're both considered to be good artists, but even so, the exhibit is for Michelangelo, not da Vinci, so da Vinci's works do not belong.

So, deleting art by non-Japanese artists is in no way "racist." The mods are not saying that non-Japanese artists are poor artists, or even that they're not good at Japanese-style art. In fact, it seems to be the general consensus of the mods that there are indeed many wonderful non-Japanese artists whose works get posted on this site, and yet even though the mods love the works, they regretfully must delete them. I have personally seen many great artists who had to go because of the rule. It's unfortunate, but it's necessary. The mods have to keep the point of the site alive.

Consider the mods deleting non-Japanese artists more like a museum curator sending the works to a different museum, because there is no exhibit in which they belong in this one.

...

Now, I have a final point to make.

This post was shit. Even if it weren't a non-Japanese artist, it would probably still have been deleted for being poor quality. It's also poorly compressed, so it actually violates a rule based on objective quality that you can't call "racist." That's right, images on this site are supposed to be good images.

If you're going to try to attack the site for it's artist policy, do it on a piece of art from a non-Japanese artist that's actually good. And, I must remind you, since Gelbooru isn't a porn site, "good" doesn't mean "makes you happy in your pants", it means that it's either well drawn, or decently drawn AND at the same time does a decent job of displaying Japanese culture via its context, dialog, etc.

tl;dr Gelbooru mods aren't racist, you're just a retard.