Really?
Today's B*itch Du Jour is that there's not enough collateral damage in Marvel movies....??
Hollywood's been ducking the collateral damage in action movies issue for DECADES. Since the medium actually began. So have comic books. It became such a running joke that Marvel even addressed it with a short-lived comic-book series with a team called, appropriately enough, "Collateral Damage," whose sole purpose was to go around and clean up after superhero battles, pay for damages, hospitalize the injured, bury the dead, etc.
Avengers is a family movie. Kiddies and their parents don't want to see bloody bodies and dead innocent bystanders. They want to see good guys beat up the bad guys. This is a no-brainer.