Earlier quoted context omitted.
The more you let people build up, the more ground can be left as green space. No one is against park. Land area/space in general is not scarce. What is scarce is land area near job centers (or more broadly, near where people want to spend their time outside the home.) The more you spread people out, the more car dependent the city, necessitating more roads and parking lots.
I don’t have any problems with people building up, but I’m very skeptical that the space between tall buildings will be made into parks, and anyway a city park is not what I would consider “nature”. For folks who want density and can content themselves with urban green spaces, I wish you well on your quest to build taller and denser, just please don’t impose that on everyone! :)
1) Cities, whether they're sprawling or dense, or park-laden or not, can be suffocating. It just so happens that yours atm is less park-laden. Thus, your advice for exclusively urban people, is to actually put the effort in to get into real nature; into the mountains, the isolated wilderness, the lakes, etc.. because there's a serenity like that you can't get with facsimiles like neighborhood parks
2) Space between high rises isn't used all that effectively. I think this is particularly a problem with downtown core areas moreso than downtown adjacent areas in a lot of cities.
I'm personally not anti-car outright, just anti-car as a primary means of day to day utility oriented travel and the design of urban spaces that prioritize that over others. If you walk or bike or skateboard most of the time, you develop a feeling for the space you're doing that in, and it has an affect on your life. If you're only walking through parking lots, on broken old slabs of sidewalk that nobody cares about, with no flowers or trees or cats or people around, you're going to want to avoid that. I'm a huge advocate for building your immediate surroundings so they facilitate healthy and sustainable living (the opposite of broken parking lots in a suburbab wasteland) but also for getting the fuck out of the whole city pretty often if you can. I rent a car to do this, and might buy a beater in the future to have more flexibility in that respect, but definitely get the hell out once in a while if you can.