That was a horrible ruling. Upholding private property rights does not restrict anyone's "fundamental rights and liberties". The two are not in conflict: no one has any legitimate rights or liberties with respect to anyone else's private property to begin with, no matter how much the property owners may have opened up their property to the public. The Constitution guarantees freedom from government interference in the exercise of one's rights; it does not guarantee the availability of other's property for that purpose without their consent.
However, the issue in this case is not restrictions imposed by property owners on the use of their own property, but rather restrictions imposed by the federal government, which is bound by the limitations on government power written into the Constitution.
Consider the Nordic "right to roam". Just because you own land doesn't mean you have the right to keep people off the land simply because you don't want them there. Or as the WP page quotes for this court case: 'ownership "does not always mean absolute dominion."'
If it were otherwise, then what's to keep from having a company city, or company state? Sell off Seattle to Bill Gates, and make it his fiefdom.
That points out that "Ancient traces provide evidence of the freedom to roam in many European countries, suggesting such a freedom was once a common norm."
It's also been noted that the freedom to roam is strongest in those areas which didn't have feudalism and serfdom.
Just like feudalism and serfdom, company towns have a history of being controlling and exploitative .. and un-democratic. That's what's wrong with them.
However, the issue in this case is not restrictions imposed by property owners on the use of their own property, but rather restrictions imposed by the federal government, which is bound by the limitations on government power written into the Constitution.