People use statistics of men claiming to have one or no friends at all, and assume that means they are lonely and depressed, but that has not to be the case. They are comparing genders... genders with different priorities, different sex market value, different expectations, etc. It is like comparing apples and oranges.

Men do not have problem being alone if they have projects and work and are happy having a purpose, rather than other people. Even male babies prefer toys like machines while female babies often prefer toys with faces. Men also relate to other men through a mission, purpose or to fight a common enemy, but otherwise they do not need each other as much (except institutionally, of course, just as women).

On top of that, even loser men today have porn, videogames and endless entertainment that can help them deal with mental illness by distraction. Sure, it is not ideal, but it is just as women dealing with it using xanax, social media, hook ups, and dating apps for validation.

TLDR: Men are naturally lonelier and prefer personal projects than developing a social life.