It's so...fascinating.... They bitch about not getting pussy and yet they do everything in their power to make sure they never get it anyway, cause I guess its Chad & "The Slut's" fault that they smell like swamp ass?
When you get somebody who realizes they're never going to get what they want from other people/society--and that they believed they were promised--it's not unusual for them to lash out by making themselves more unacceptable, or even repulsive, to the people who "failed" to deliver. It's a coping mechanism for dealing with deep disappointment that life hasn't turned out as your childish fantasies led you to believe it would, and the hurt, envy, and resentment that accompany it.
Is it a very healthy, productive way of coping? No. But it exists nonetheless.
The weird, outcast kids who tried for years to fit in at school--wear the right clothes, have the right interests, listen to the right music--only to realize they're never going to fit in and be normal, no matter what they do? They're the ones who adopt whatever the latest ugly/scary/controversial hairstyle and clothing subculture style is. (And, to be fair, they usually outgrow this.)
Ugly fat girls who finally realize that the fairy tale is a lie, and that no guy is ever going to love them for their "inner beauty"? They're the ones who go all-out with the dangerhair, tattoos, loud and/or revealing clothes, creative gender designations, FA rhetoric, and loudly bragging about how much Vitamin D they get (even if it is just with guys who are into hogging).
And in this case, Mr. Stinky here is an unfuckable sperg who expected that he would of course be able to acqire feeemales--only to discover that actual women are free to reject him based upon desires and expectations of their own, and that he consistently doesn't measure up. Also, despite whatever ideas about his own superiority and assurances of future success he may have grown up with, he's now in an inferior position to not only desirable women, but also to men who can attract them. So other men, who have what he wants, and feels entitled to, are enemies as well.
Thus, he has decided that the whole "normie" world is against him, and it's their collective fault he doesn't have what he he rightfully deserves, so in retaliation he's abandoned the most basic element of social acceptibility--hygiene.
By stinking up the whole train, he gets attention, rather than remaining a nonentity. This is one social situation in which he has all the power and is the center of attention, even if it's only to disgust and offend his perceived enemies. As long as he's occupying that train car, everybody is subject to his body odor; nobody can ignore him.
He already knows he is only going to be rejected, so this is his way of saying, "Fuck you! You want to reject me? You're not going to give me what I deserve? Well, I'll give you a
reason to reject me!"