The Republican version of this would be
"Hi kids! Only the kid with the most candy gets more candy. The rest of you kids can wait until it falls out of his bag!"

That's not bad!

So far the best I could come up with was:

40% of the candy will go to the richest 1% of the kids on the block. Candy-givers will know these children by their $150k costumes.

Liberals are funny.

What? You want me to just give you a handout? You kids are just showing up on my doorstep and I'm supposted to just give you candy? If I just give you some chocolate, the next thing I know you'll be gay-married in California living off of welfare that my taxes pay for. You need to pull yourselves up from your bootstraps like I did, so I can afford my own candy and not go around begging people each night. Instead, what I am going to do is give you each a copy of The Fountainhead and you'll understand the value of your own hard work.

You already can't afford to have your existing cavities filled, so how much can another Snickers really hurt?" Another round of high-fructose corn syrup for everyone!

"Lucky kids! If they'd gone to a Republican's house, all of the candy would have been given to Wall Street bankers and CEOs already!"

How cute -- a little Reagan, Rove and Coulter! You can have all my candy and civil liberties!

Replace dialogue with:

Oh dear! A Ghost, a Devil, and a Witch. Obviously you are children of satanic, godless, tree worshipping liberals! Have you found Jesus? Here, have some WWJD candy.

Kid:

WWJD? Jesus would slap the shit out of you, asshole.

The old man is too greedy!