It's no excuse to be evil, far from it, but does if morality is a human construct, does that point to us being designed?
morality would point to design if it was the same everywhere and remained the same trough history. that is clearly not the case so something must be effecting the moral compass of humans the most probable influence would be social and religius influences.
if you take slavery for an example throught history slavery was something normal, in some places it would have been considerd immoral not to own slaves if you could afford them a social stigma was aplyed to people that worked when they did not have to. in todays times it is immoral to own a slave even more than immoral its ilegal it went from a unwritten social norm or moral to a written law.
one could argue that god dint like slavery and ispired humanety to abolish it, you would haveto ask yourselve why would he condone it in the first place its written in the bible if you beat a slave and he dies you will get phunished but if he lives for a cuple of days after the beating you wont get punished