Umm, no, most criminals were not executed, they were transported, first to the Caribbs (yes I agree that was on grounds of labour) or the Americas, and later Australia.
Transportation was very much an out of sight out of mind thing.
I suggest reading "The Fatal Shore" and listening to the "Transports".

Sadly, nobody did much to stop the death camps in WW2, so please don't start arguments on my guys were better than your guys.