Except that, as this discussion has made repeatedly clear, there are two very different ways of looking at it, and people do see that as letting someone else choose what they wear. It's still their character being presented in a way they didn't choose and may feel uncomfortable about.
You can make your argument be about the green metallic pigs who are doing it to annoy, but it's not the only motivation people have for not wanting their character altered. As we have covered so very many times here.
You can have your own opinion on whether their feelings outweighs your desire to not see their outfit, but it doesn't stop people from feeling that way. You are choosing the attire of an extension of their character or personal avatar if you have the ability to alter other players' characters, whether they care or not.
The only question is where the border lies between their rights and yours, and increasing your rights cannot happen without decreasing theirs.