The average park in America is only like 5-10 acres. And of that only certain areas may have playstructures / basketball courts / benches / other things that people can actually use. So sufficiently loud audio can ruin people's experience. It's obvious to anyone who's been outside in the past 10 years that "live and let live" doesn't work... if they were using heroin and nodding out would that just be another form of recreation?

Yes, and the crime spike of the 1960s started with boomers reaching 15-20. You can follow that to cookie monster pajamas in Walmart.