"genetically wired to" means it is a part of our nature. We are predisposed/predetermined to be like that. It's innate. Wires are part of the internal structure of a machine, if you swap them around or take some out, the machine might behave differently. It is the same theme here, our genes and DNA are the 'wires' that determine what we will be like. E.g. "People aren't wired to learn a language just by reading grammar books" / "He didn't believe them, as usual - he was wired to be suspicious" Another similar 'machine' metaphor might be the word "programmed."

Thank you Nanren888

Yes, nature versus nurture - a long-standing argument. "wired for" is the nature side of the argument. . Often used as a over simplification of why something is as it is. . Humans tend to think symmetric is better than assymmetric. If virtually everyone has the same impulse, we can describe it as "hard-wired", set in place as a starting point. This does not mean that we cannot rationalise arround it.