..And I am feeling sorry for poor forgotten Livejournal. Here, Livejournal! Have some headcanon!
Gaston (likely along with the other town leaders) is a revolutionary. He's been trying FOR YEARS, basically his whole adult life, to build a town where people don't need to depend on royalty; handling the usual royal duties like defense and land maintenance so the province/town (boundaries of the unprinced lands are unclear) that pays fealty to no ruler, and keeps the rewards of work for the working class.
Thanks to the caprice of the witch (or was she in league with them?) this has all been achieved without the bloodshed of most revolutions. It must have been a stunning moment for the town- waking up one day to find their world- recognized official governor disposed of, their army gone. But they went with it! Gaston took on the military and border patrol leadership, the merchants organized themselves, and the farmers managed their lands according to their own experience. And they kept their royalty-free status secret from the rest of the world while they got their feet under them.
And it was working, dammit! The town in BatB is prosperous, peaceful, and friendly. They eat meat while most people in their class struggle to find bread; they have a library, even if they haven't got universal literacy yet. All they had to do was keep things moving smoothly, and not have anyone fall in love with their heartless, hidden former-dictator, which, geez, who would?
The town's doing so well they even make room for an inventor and his frankly rude daughter, accepting their arrogance and aloofness as simple "oddness", even while she outright sneers at them in their work. (This Belle is perhaps more believable as the daughter of a prosperous man fallen on hard times than the usual fairy tale version, but she's a problem in a community held together by common cause in an age of kings.) Everyone in town tries to include the inventor family in their community; Gaston straight up asks Belle to marry him, which would put her in good association indeed.
And Belle's reaction to everyone is : Ewwww, PEASANTS.
Gaston does not deal with this well- but he does leave Belle to her own devices, instead of rolling out the tumbrels and such. And on the romantic end,how bad a reaction is "a night of drinking with my pals"? He's well on his way to getting over it altogether, when in barges Maurice, full of news about "the Beast"- the Beast every adult in town knows is their former prince.
The Beast who now how has a daughter of the bourgeoisie locked in the palace,where he can seduce her and break the spell that's kept the town free for ten years.
And suddenly Gaston's got to make some bloody choices. The Broadway soundtrack highlights this as the moment when Gaston knowingly chooses damnation in the service of freedom. He acknowledges his scheme is dirty, even his closest advisor warns that it's dangerously immoral--but he 'won't even be mildly remorseful, just as long as (he) gets what (he) wants in the end'. And what does he want, after all? The continued freedom of his town and people. So jailing one old man, to lure his daughter back out and away from the Beast, seems a small sacrifice.
But when Belle does come back to the town, it's clear it's too late for such a strategy; she's 'in love' with the Beast (others have written plenty about the problematic nature of love between a hostage and her prisonkeeper, so I'm letting this go mostly uncommented)- at least enough to satisfy the spell's requirements. Desperate to find some way to keep the revolution peaceful, Gaston again tries to get Belle to swear allegiance to him and the village, through marriage- but she won't.
With imminent re-installment of the monarchy looming, the villagers turn to the grim solution of a thousand revolutions before: Kill The Beast (though they STILL don't turn to killing the collaborators, Belle and her dad, a move that will cost them). Read the lyrics to that song as a political protest. It paints a bloody picture of the former Prince's reign (perhaps never known by Belle- would you tell a woman who dreams of magic and princes that you have magic cursed prince when your life depends on keeping him cursed?), along with a grim resolve: We're not safe until he's dead. The spell isn't enough. And note Gaston's still setting himself up to take on the group's dirty work."Remember, the Beast is mine!"-- the others are free to reclaim property, but he'll be the only one to take on regicide, the figurehead to blame if things go wrong.
Which of course they do. "Love" and privilege carry the day; the story ends with townsfolk back in their proper place, dancing attendance on Queen Belle and King Beast...but there's been no obvious wave of repercussions. Gaston, in death, has all the blame for the attempted uprising.
Beauty and the Beast is a villain-protagonist story, dammit, and the villains win.