Oh, they have the same God-given sense of logic and reason that everyone else does (though twisted and perverted), it’s just that they start from the opposite end of the board on their assumptions of the nature of mankind.
If two people have a set of directions, but one starts from the correct starting point and the other at the wrong starting point, they both can follow the directions to the letter and one will end up at the right place and the other at the wrong place.
It’s interesting that Christians understand the depravity of man, yet because they know that man is made in the image of God, they respect human life and care for the weak and helpless.
Liberals/atheists will deny sin and will say that humans are “evolving”, growing better and better, yet they have complete contempt for human life and consider humans as pieces of trash to be disposed of, while going to ridiculous lengths to protect and nearly worship creation itself (all except for humans of course).