People don't. People don't usually understand most people suffering from mental illnesses. If people did understand what incels are, they wouldn't turn the term into another buzzword insult du jour.
Killing all incels is a step too far. But making fun of people for posting rape fantasies on the internet, pedophilia, or encouraging others to get multiple plastic surgeries is something that I can't argue with.
There's a good number of lonely men who have an incel-like phase, and a few who have full blown incel phases and post on incel forums. The men who can be saved usually get help for it, whether it is inadvertently by falling into a job or a new living situation or by choosing to change/talking to someone professional or people they love. There's incel men who have real depression, anxiety, bipolar, autism, and other such illnesses that fall through the cracks and turn lonely and bitter and become the older wizards. This is a problem with our attitude towards mental health and our lack of good care across most nations along with a general misunderstanding of how family and friends should treat diseases and disorders like that. This will take years and generations to fix, something we should aim for but don't have the ability to do so overnight. My heart goes out to the incel brothers and sisters (lolcow and twitter) who are just legitmately lonely and depressed with bad social skills. These fall into a bad crowd and can parrot things online without acting on them IRL just to fit in.
Autism & mood disorders are no excuse for posting long diatribes on things you know are morally wrong and doing things that are morally wrong. Acting out spitefully towards others is something you are taught not to do throughout all of K-12, and even though mental illness is heavily influencing you, there is no excuse for trying to rally others into detrimental activities like lookmaxing and being nasty to IRL people trying help. Men who get too into it, whether it be long Hitler-blaming-Jews-but-replace-it-with-women diatribes or advocating for rape and pedophilia are inexcusable. They know it's wrong by society's standards but advocate for it anyway. Those who act on said impulses to commit crimes or just generally be a dick to people have the same problem Chris has, where yes, the disorder influences them, but they're competent enough cognitively to know right from wrong and choosing to act on your shitty impulses is still a choice. Men (and legbeards) who spitefully engage in destructive behavior and refuse to change even with help (no its everyone else who is wrong) are failing themselves and there's not much we can do for those types aside from make fun of how pathetic they are (we are here for cheap laughs after all) to show flaws in their logic so others do not follow them into the dark.
I have more sympathy for the looksmaxers but even then I stop at a certain point. Body dysmorphia in males is almost never addressed, and needs more study. The gay male community can tell you that. Posting anorexic positivity type threads encouraging others and yourself to harm themselves is something that should be stopped, and without taking down the forum or being able to pry these people off the computer (we're not their IRL family or friends) the most we can do is constantly point out flaws in the logic and make fun of it. We could try to be nicer to the men who do it, but this is not the site to do it on to put it mildly.
Those of us who know incels IRL or as internet friends will do our best to try and steer them away. Several farmers have talked about trying to help cases IRL and whether or not they've been successful. However, there are always going to be men (and legbeards) who choose to be hateful bastards and throw themselves further into their ways. These people do not want help, they want to throw tantrums and have the world conform to them. These people are the ones most threadgoers prefer to make fun of on this site dedicated to humans making terrible choices and not changing their ways, but yeah we can get cheap laughs out of those suffering too.
TL;DR: this is a site dedicated to making fun of people regardless of mental stability and lets people do free speech even if the jokes are dark, we're not here to moralfag even if irl we try to help our friends and family who fall into this. Rape and pedo advocates should get the rope as well as spree shooting retards (and glowies need to stop encouraging them too yeah). A lot of us have sympathy but we again aren't here to parent people, we came to laugh at others.
Edit: spelling thanks to phoneposting.