The following is just a theory, of course.
Even though US society has an ever widening gap between the very wealthy and the misfortunates who have to slave away to maybe get somewhere in life, many people still believe in the American dream.
The American dream is usually a nightmare where people work their ass off and never get anywhere. A lot of Americans are one unlucky event away from total bankruptcy. They can’t afford illness, a broken down car, any kind of unplanned for extra cost.
The more you believe in the American dream the more you will feel cheated and the angrier and sadder you will be once it becomes clear that the American Dream scenario works only for a few very smart, very lucky, very hardworking and very well connected people who happened to be in the right place at the right time.
African-American and all non-white men in the US know that the game is rigged and that they are extremely unlikely to ever become mister Big Shot. This protects them against dangerous illusions, depression and frustration.
Plus men have it harder to find sexual partners and rebound worse from break-ups and divorces. Americans are also very lonely and often disconnected. All this raises their suicide risk.
Men are also ‘better’ at committing suicide. Women attempt suicide too, but often unsuccesfully. Probably because of the methods used. Men are more likely to use fire arms which are more effective.
Important note: I believe that most suicides are a prevented murder. Meaning that the person who commits suicide is angry. Instead of lashing out he opts to direct the violent urge towards himself and ends up dead.
For all the reasons mentioned above it’s also usually white men who go on killing sprees and organize a mass shooting.
Short answer: white American men feel like they were promised they would inevitably make it big in the ‘greatest nation on earth’. When they find out they will not, they cannot cope.
Women are a bit more protected from this as they tend not to take economic faillure so personally. They have other things to compensate. Men tend to tie their whole identity to how much money they make and how they rank in the social hierarchy.