It was Donald Rumsfeld who said "absence of evidence is not evidence of absence"... In regard to supposed weapons of mass destruction in Iraq.

Excess males without a mate are prone to antisocial behavior such as crime and violence. When they congregate in groups they tend to organize, form paramilitary groups or join the military or engage in revolution or terrorism. See https://www.ncbi.nlm.nih.gov/p... 94% of unmarried males in China are poor and uneducated because they are the least desirable partners. They are more likely to be susceptible to demagogues or nationalists. Sex ratio imbalance in the other direction is also a problem. A shortage of men results in fewer committed relationships, more single parent households headed by women. Men in these situations tend to be underemployed because they have less reason to work and are often supported by women... because they can. Even small imbalances can have these effects; a sex ratio imbalance of 110 in a population of 100 million will result in 10 million people without a mate.