I totally agree with you, but there are different kinds of people and in this case they considered this to be ok and for the most people it was because there was a lot of beer available...
It depends. Because I have thrown parties in my garage do to not wanting a bunch of people tearing up my home. But I didn't leave the car inside and my garage was huge so it actually worked out very well. After the first time we never had a party inside our home again! Lol
What sort of parties are you having Vicenta? I am guessing a lot of alcohol involved because you say tearing the home up? Either cases, I understand that, but it was not the case because it's an "older" people party with kids involved.