I've been modding for probably nearly 20 years in car games now and some modders always get a bee in their bonnet over 'their' stuff being re-used elsewhere.
I wouldn't really say a rare situation. I'd say an everyday one
Just because you *had* some ability to rant and rave about people using other modders content without permission in the official forums and get some sympathy, doesn't really change the fundamental point that modders need to grow some really thick skin.
They need to just appreciate those who do appreciate it, and forget those who will mod it and re-release it and whatever else, no matter what you might try do about it.
I can certainly understand why KS didn't want to moderate that kinda stuff.
Just running a forum is a pain in the arse before you have to actually moderate ranting people