Imagine this: you grab a nice looking TDA mmd. You find some cute clothes from DA to put on. It looks a little scuffed because you're bad with blender and combining stuff, but that's okay, no one's perfect. Sure, her/his face looks the same as any other TDA, but just because you're not unique doesn't mean you don't look good.
Then you change the hair color. Hm, should you choose a more normal looking hair color? Naw. Let's do something anime like red, black, blue. Should I make the color more muted/less saturated so it looks natural? Naw, it needs to be bright and saturated so everyone can see me. You can barely see the original texture now. We're going to also make it glow so that it now looks like a single bright colored blob instead of allowing us to see the contours of the hair.
That hoodie? Its pure vantablack now. Its just a black hole that sucks all light.
You're going to also emblazen glowy tattoos all over the body. You don't want a small hard to see tattoo that can only be seen up close, people have to be able to see it all the way from spawn.
Look at this avatar now. Its a piece of shit. Why do people think this looks good?