Atheists may not believe in God, but I think they mostly adhere to the 10 commandments.

I think you're just trying to say that atheists follow moral expectations of modern Christian-influenced culture, but taken literally, the statement's nonsense.

I mean, look at the Ten Commandments:

1. Thou shalt have no other gods before me.
2. Thou shalt not make unto thee any graven image (...).
3. Thou shalt not take the name of the Lord thy God in vain (...).
4. Remember the sabbath day, to keep it holy. (...)
5. Honour thy father and thy mother (...).
6. Thou shalt not kill.
7. Thou shalt not commit adultery.
8. Thou shalt not steal.
9. Thou shalt not bear false witness against thy neighbour.
10. Thou shalt not covet thy neighbour's house, (...) nor his ass, nor any thing that is thy neighbour's.

The first 4 are blatantly ignored, 6 is famously problematic, 9 and 10 are mostly ignored (via gossip, status seeking, greed and so on) and finally 7 and 8 might be typically obeyed, but minor theft (especial anonymous) is common and adultery has at least 10% base rates.

How is this a "mostly adhered"? (Obviously, Christians and atheists don't really differ in their behavior here.)