Are selective pressures breeding aggression out of first-world populations?

I was reading about the genetic component of aggression, specifically the so-called “warrior gene”. This gene has to do with producing an enzyme that breaks down neurotransmitters. Males (the effect doesn’t seem to hold for women) who possess certain alleles of this gene tend to respond more aggressively when provoked or in stressful situations and exhibit riskier behavior.

Some populations have a relatively low incidence of the implicated alleles. About a third of Western males have it. In other populations it can be twice as frequent. The Maori tribes of New Zealand are an example of a high-incidence population. Evidence indicates that environmental factors play a big role in whether having the allele triggers actual aggressive behavior.

It seems possible then that how different cultures view aggression might tend to select for or against the genetic factors. Getting into more fights and taking more risks might increase your chances of getting killed, but it also might do wonders for your social status and increase your appeal as a mate in some cultures. Maori culture honors the warrior spirit, ritualizing it in their haka chants.

Could it be that having that gene variant has become more a liability than an asset in our culture, mating-wise? Is the sex-appeal of aggressive men wearing thin here, overall? I can certainly think of counter-evidence, but what about the general trend? Is there a general cultural disenchantment with aggression? Will that make us less genetically disposed to aggression in the future?