(speaking largely from a cishet frame of mind here, since that's mostly what I'm familiar with) (also, caveat, I don't know anyone personally that would identify as an incel)
I mean, 'inceldom' IS largely an individual problem, because the cultural pressures that seem to produce the phenomenon, including suburban hellscapes and gathering points costing money, affect everyone. There are absolutely societal changes that it would be good to see- absolutely would it help to have social centers more accessible, absolutely the digital dating scene is a monetized, gameified hellscape, absolutely toxic masculinity is harmful to just about everyone. We absolutely need better discussion about emotionality and emotional support, and more onto that, emotional education so men don't outsource problems and baggage to the first woman that offers a sympathetic ear, or expect that simple compassion should lead to sex or romantic interest.
The problem, in my estimation, is that 'incels' take these cultural pressures personally, and wrap this general cultural victimization into a personal identity, and then take challenges to the notion as a challenge to their identity and become hostile and fall back into groups that won't threaten the integrity of this new identity.
And then the far-right says 'this identity is valid, let's hurt the people who wronged you,' because the far right always, always, always needs someone to be at fault or someone to blame or some kind of enemy, because retribution is a lot easier to call for than systemic changes, and young men who have learned to respond to emotional stress with violence are easy to weaponize. It's opportunism to reinforce power structures without meaningfully addressing societal issues. As Vec's pointed out, this doesn't work for the left, which wants solidarity and social change. That's hard work and much slower to produce the results that might better fix the problem, and can't validate the incel identity because again, that's an individuated response to social problems. You can't really say 'we have changed society so you can fuck' without some party being outside that society.
From what I've seen in one or two women-centric social media spheres, there's frustration when someone presents a general or systemic frustration and then someone jumps in with a "not all men do that," because of course they don't, it's a generalization and generalizations have exceptions, and any general claim that 'all men do xyz' similarly has exceptions, so taking the former point as requiring defense and the latter point as universally valid criticism just distracts from the discussion that there are systemic issues with how we view and handle genders. Stop taking it personally, it's not about 'you,' whomever 'you' may be.
In my opinion, and speaking broadly to men here, if you want love, be a better brother to people. Trade expectation for compassion. Be tender to your fellow men so it's not associated with romantic interest, and gently dismiss the idea that it's some kind of gay if it comes up. Toxic masculinity is intertwined with homophobia, and we have to do our part to correct both. Have someone's back simply out of concern for their wellbeing. I agree with Rolan here- nobody owes anyone love, except probably to oneself, and sometimes that's hard work too. The problems and concerns surrounding your gender are not specifically your problems, but you can absolutely be cognizant of where and how you may contribute to them. Don't take it personally, don't prickle, but ask and listen.