The trees and parks are available to everyone to enjoy though and can be used for many different things, almost surely to appeal to everyone in some way.

A sports team and a stadium have a very narrow appeal and is inaccessible to a large segment of the population either due to disinterest or lack of funds.

I get your gist here but I think it's pretty easy to make a distinction between these things. Even the most hardened Libertarian would agree that public spaces like parks are a net good.