I mean, capitalism isn't the but-for cause of everything.

I suspect it is more that some people just don't like teenagers and get angry when they are out having fun. I also suspect some teenagers who are assholes that run around town smashing stuff ruin the fun of Halloween for others.

Either way, I've never seen institutions of capital - from Clubs and Bars and Party Venues to Schlock Merchants and Candy Vendors - shy away from selling Halloween as an All-Ages Consumerist Event. The folks that are the most curmudgeonly about it tend to be the helicopter parents who are terrified of the neighborhood they live in and angry that they've been forced to leave their fortresses of solitude at all.