First, we have a significant body of law going back to the 1950s and early-1960s around exclusion from private spaces generally open to the public, mostly revolving around the ability to maintain segregated parks when ownership was held by private parties. This predates the 1964 Civil Rights Act and its implementation and relies instead on the 14th Amen. prohibition on state discrimination following Brown v Bd of Education of Cleveland. Some also goes back to the "company town" cases. In any event, take as given that Zuccotti Park can (and, I believe, under applicable law, should) be treated as owned and operated by NYC for 1st Amendment purposes.
Under the 1st Amen., it is generally not permissible to target speech based on its content or the nature of the speaker. Such rules are subject to "strict scrutiny," which I shall not explain here, but is generally regarded as "strict in theory, fatal in fact." However, a state or federal government may impose "reasonable time and place" restrictions to ensure that all parties that wish it have reasonable access to the public space, that the purposes of the public space may be carried out, and that public health and safety is protected. Critically, however, a reasonable time and place regulation will be subject to strict scrutiny where there is evidence that the regulation is, in fact, motivated by animus to the speech itself, or to the speaker. There are criteria for making a fact based determination on this issue.
Here, it is undisputed that, prior to OWS, Zuccotti Park had no rules prohibiting the erection of tents, camping, or sleeping in the park. These rules, on which the City and Park owners rely for the eviction, were put in place after OWS set up their protest and began to attract national attention.
There are two ways to interpret this. One is that the experience of OWS demonstrated the need for the City/park owners to put in place reasonable time and place restrictions. It is not a per se violation to adopt rules after the fact, and in the face of ongoing behavior. To the contrary, sometimes the need for a rule is not clear until someone does something that demonstrates why a rule is necessary for a permissible purpose. At the same time, however, post hoc adoption in response to a specific speaker or speech can demonstrate that the assertion of a reasonable time and space motive is mere pretext for content/speaker based discrimination.
The court's order is rather terse, which is not surprising given the exigencies of the circumstance. But the facts indicate why this is a more interesting 1st Amendment question than one might assume at first glance. On the one hand, the character of the rules is consistent with reasonable time and place restrictions. On the other hand, it is also possible to make a prima facie case that NYC has a particular animus to the speech and speakers. Further, it is relevant (but not determinative) that the prohibited activity was clearly, at the time the regulation was adopted, a form of protected political speech, and that no other mode of speech consistent with the rules is as effective for the purposes of the speakers.
Unfortunately, the court's order does little in the way of explicit balancing of factors. It simply finds that the protesters' 1st Amendment interest does not outweigh the importance of maintaining general public access and reasonable public safety precautions, and relies on the representation that protesters will continue to have 24-hour access to the park subject to the rules against camping, sleeping in the park, or storing gas and other potentially hazardous materials in the park. On appeal, if there is one, I would hope to see the 1st Amendment issues played out a bit more thoroughly.