This is because the US labor laws are messed up. In other countries, you get paid overtime even if you are salaried.
I'm voting with my feet though. Should be getting a job offer (hopefully!) in the next few days.
Another factor is if you fall sick or can't work as usual for some reason. Australia has laws which make it hard to get fired (unfair dismissal legislation), providing even more security to the salaried.
TOIL and on call allowances are not the same as paid OT here.