Josef Mengele valued facts. Did tons of research finding all kinds of amazing new facts. Just wasn't too concerned about the people he did his research on.
Exactly -- by *his* definition of "humanity", i.e. "people like me". If he hadn't lived in a place & time where someone that twisted could get a high-level government position, he probably would've turned to serial killing.
Of course one could be good without God. There are many fine people who are agnostic. The purpose of acknowledging, worshipping, and following our Creator is in the knowledge that He created us out of love and desires a relationship with us.