Christianity and morals

[John V]

Christians claim to get their morals from God and the bible. But they clearly pick and choose the good stuff from the bad in the bible. They like the part where jesus feeds the 5000 but overlook and ignore all the slavery, genocide, murders and rape. To choose as they do, from the bible, they would need an already existing and separate set of morals. Does this not prove that they don't get their morals from god?

I think I heard this argument somewhere on youtube but cannot remember who said it so I cannot give credit where it is due. Just wondered what Christians would say to this. And don't you dare say: God is so ingrained into society that we follow his morals without even knowing they are his morals. Because that is bullshit.

This Christian says you should research it yourself and try to present a cogent argument. "I think I heard this argument somewhere on youtube..." Seriously?