If someone reports Midas Magic saying Xilver didn't get permission to use some assets in the file I'd laugh at them, and probably either warn them or ban them. If someone reports a file I don't know about, and I look at the file and see the author has specifically said they didn't seek permission from all the authors to use their work then of course I'm going to pull it. I really fail to see where the issue is here.
If the contributing author isn't the one complaining, then in what crazy-[censored] world do you live in where pulling the mod seems like a reasonable response?
Let's look at how this works in the real world, shall we?
Person A creates thing 1.
Person B buys thing 1, illegally copies it, and sells it as his own.
Person A sues person B.
Alternate scenario:
Person A creates thing 1.
Person B buys thing 1, illegally copies it, and uses it for their own personal enjoyment.
Person A doesn't care. Nothing happens.
You see how in the real world there are circumstances where the creators - the people who should be making these decisions,
i.e. not you - make decisions based on circumstances and logic rather than ad-hoc policy?