I'm not suggesting we get rid of all street parking, but it's currently at absurd levels. It would be great if some of those subsidies went to something else that lessened the need to own a car in the first place.
You don't have to pay to do those other things either. You might not be able to because of safety reasons (e.g. a BBQ in some places) but the "for free" isn't relevant.
I mean, the traditional answer is pretty clear. Roads are public transportation infrastructure. Parking cars (and bikes and scooters) is allowed, because cars move the public around. All these other things are not transportation for the public. People think of parking spots along the streets as "landed property", but they're not, they're more like the overhead bins in a bus or plane.
But also, from a practical sense, no one cares about public transportation anymore, so you actually can now park random crap in the street, anytime you'd like?
At least in Michigan, restaurants routinely do the "park a picnic table with a BBQ on the side of the road" thing all the time (see https://www.giffelswebster.com/dining-platforms-and-parklets...) -- many of which still persist since COVID assistance ended.
And residential/commercial construction workers routinely do get to block off street parking for a tablesaw or any other construction usage at job sites all the time.
It's like thinking that people pay income tax but companies pay employment tax. Companies would happily pay you the employment tax, as they've already budgeted paying that much for you anyway. Thinking this is some free money that doesn't affect people is incorrect.