Maybe this curse in Genesis 6:3 wasn't meant for the few descendants of Noah.
Maybe it was an exception to the few after the flood.
Genesis 11 tells of the long genealogy between Shem and Abrams where almost
every person mentioned lives longer than 120 years.
But i agree with "ttdtt", it's all BS....
My question why a 120 years when "Supposedly" man was living 900 years.
Hell that would be like God cursing mankind today, your days will be 5 years and you
will kick the bucket. Thanks God you are a likable guy.