The Avengers bloody rampages

But none of those guns or massive creatures would've even made it to Earth if the Avengers had done their job properly and simply gone into space and destroyed the Chitauri mother ship before the Chitauri could invade.

Many MCU fans have criticized Superman for taking the battle against Zod to Smallville. So by that same standard, the Avengers should be criticized for letting the Chitauri invade and then battling the Chitauri in Manhatten (where there are millions of civilians) rather than going into space and battling the Chitauri in space (where there are no civilians).

If the Avengers had gone into space and battled the Chitauri in space, then there wouldn't have been any human casualties. So a thousand dead from the Battle of New York is a huge number of dead considering that there shouldn't have been any human casualties if the Avengers had simply done their job properly.

Wasn't that Nick Fury's reason for forming the Avengers? To get the job done and save lives? Well, the Avengers didn't do their job properly and many civilian lives were lost because of the Avengers' failure to do their job properly.

Superman doesn't have a nuclear missile. But Superman could've gone into space and destroyed the Chitauri mother ship and ended the invasion before the Chitauri got to Earth. Are you saying that the Avengers don't have the equivalent firepower or weaponry of 1 nuclear missile? If so, then why do they call themselves "Earth's Mightiest Heroes" when they're mighty at all?