Why is more african american acting like darkskin and light skin is two diffrent races?

i've been wanting to scream...first off i'm an darkskinned woman ( think of an gabrielle union but an inch darker) first off i had guys tell me they would date me if i was lighter, or i'm cute for a dark girl....SN: THESE ARE BLACK GUYS SAYING THIS...smh really guys is it that bad to date a dark skin girl..how is it that lite skin girls are pretty because they lite skin....i've meet alot BEAUTIFUL dark skin girls and they all have gotten the " you cute for a dark skin girl " or i don't like dark skin girls. GUYS can i get your opinions on this PLEASE (ANY RACE)