The implication is that society is also very hostile to men and boys right now, demonstrated by them becoming incels in large numbers.
Because, I know from past experience, that only a small minority of these 'incels' have done anything seriously wrong, and the rest are going to end up on government watchlists for expressing the wrong political opinions. Political opinions that have been deemed inappropriate by pressure groups which are influencing the government to enforce their agendas.
And because of the lack of separation of powers nowadays, we will have intelligence agencies such as GCHQ monitoring the Internet, using powers that should be only used against foreign states, turned against the general public to hunt down these 'incels'.
Yes, these pressure groups have so much sway over the government, they can even eventually get GCHQ to enforce their agendas. Many of these pressure groups being fronts for those with radical feminist or evangelical christian agendas, i.e. they are the modern equivalent of puritans.
This stuff plays out over the decades, and finally we got to the point where we are now, after extensive lobbying by these groups for a very long time indeed.
And it's ruining society, these pressure groups are in effect, a national security issue and nothing is being done about it by the government.
Thus, while it may be the western version of some exotic sounding Japanese word that translates as "single adult", the implication is the exact opposite causality of your question: they are single because they are bad, not vice-versa.
Being an incel is something you choose. Everyone else just isn't having sex.
But a lot of them act in bad ways because they believe/have been told to believe that their difficulty in finding a relationship is someone else's fault.
This often makes them utterly insufferable to be around, which is a positive feedback loop.
And then, hey, look, here's a disaffected community of angry young men, all feeling that society has taken a great big dump on them, all ripe for radicalization by some cynical ideologue.
They are bad people because incel forums are normally filled with crab-bucket mentality users who regurgitate highly misogynistic tropes up until the edge of being openly violent to women.
If you are unable to see the misogyny towards woman in many incel communities for whatever reason, at the very least I would say that they are bad for men because they tend to grow by reinforcing the idea that their community will never be good enough, that there is nothing that they can do, and it is the fault of society for all their problems.
If you are going to sit here and pretend Elliot's manfesto wasn't misogynist, then so be it, there's no point to carry water for these guys.
The first paragraph speaks for itself. The whole "involuntary" part of "incel" implies that your celibacy - the fact that people don't want you as a partner - is totally out of your control. Incels are the epitome of "nice guys".
It is common to see some one with that mindset to see outcomes as inevitable or as a function of things wholly out of their control such as looks or a perceived social dynamic involving 'chads' and 'staceys' that they are ineluctably locked out of.
Just some real bad vibes.