I somewhat agree with Mr. Kelly.
Before I met my wife, I lived in an apartment building in a neighborhood with people who were definitely firecracker enthusiasts on July Fourth. And the one time I tried calling the police (after stopping counting at hearing over 500 firecrackers), the lines were jammed.
And that was just one small section of a very large city. Denver doesn't have the resources to chase down all such enthusiasts.
If the police catch do a firecracker scofflaw, what are the police going to do? Arrest him or her? Hardly.
So, (in life, there's always a "so,")
It boils down to a matter of priorities.
I eventually discovered that running a box window fan with the windows closed did wonders to create white noise.