It's sad companies had to destroy these fan made projects...

According to law if they treated them on case by case bases (and let the good ones slip by) they'd lose more money than if they shut everything down before it get any support. Actually if they made some "good" cases, they might lose the right to object to the "bad" ones as well.

And believe me, fans can do terrible things... See how many mods of Skyrim can turn it into an X-rated game.