So would you endorse it legally? It was the solution to the crisis in Netherlands. You used to tell the local police station that you were occupying the house.
It does happen without legal recourse. Since the USA doesn't have a registered lease system (no registration, police don't care), anyone can take property and claim it is theirs, and live there while the courts sort it out. This includes just going on vacation for a couple of weeks.
It isn't a solution to anyone's problems except maybe as a way to live free while doing lots of drugs.
I'm not sure what you mean by protected. A squatters life is to find one squat, wait until the courts/police kick them out, and then find the next one...wash rinse and repeat. It isn't a great life, but people do it, which sucks if they happen to choose your house.
So, some countries have protections for squatting.
Squatting is legal.
In the USA property rights are very strong. Read the article I posted earlier. Basically in Amsterdam a lot of companies were colluding to keep apartments empty which inflated the price. In response people were legally allowed to squat the apartments provided they were unoccupied.
This fixes the problem of empty apartments.
Comparing the rights of squatters in the USA to the rights of squatters in other countries is a non-starter. I'm saying if citizens in the USA had the same rights to squat as they had in the Netherlands in the 70's and 80's the problem would be fixed.
It isn't a solution to anyone's problems except maybe as a way to live free while doing lots of drugs.