This all makes sense but these examples are not "squatter's rights" as they
do not have any.

The example all appear to be donated land space and labeled "Squatting"

I cut'n pasted a website text in a previous text that defines the US laws.
It claims for all states.

It has to be voluntarily given away.

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Well...not exactly totally true...close...but....

http://en.wikipedia.org/wiki/Squatting

United States of America

In the United States, squatting laws vary from state to state and city
to city. For the most part, it is rarely tolerated to any degree for
long, particularly in cities.[60] There have been a few exceptions,
notably in 2002 when the New York City administration agreed to turn
over 11 buildings in the Lower East Side, which had been squatted in, to
an established non-profit, on the condition that the apartments would
later be turned over to the tenants as low-income housing
cooperatives.[61]
[edit] Occupancy issues

Laws based on a contract-ownership interpretation of property make it
easy for deed holders to evict squatters under loitering or trespassing
laws.[31] The situation is more complicated for legal residents who fail
to make rent or mortgage payments, but the result is largely the same.

Most squatting in the US is dependent on law enforcement, and the person
legally considered to be the owner of the property, being unaware of the
occupants. Often, the most important factors in the longevity of squats
in the US are apathy of the owner and the likeliness of neighbors to
call the police. This was not always the case, particularly in the era
of Westward expansion, wherein the federal government specifically
recognized the rights of squatters. For example, see the Preemption Act
of 1841.
[edit] Legal protections

long details snipped