Isn't there a caveat? The article (unlike the headline) says "blocking people based on political speech" is forbidden. However, he is still free to block trolls right?
That case isn't about "trolling," it's about causing physical harm to someone through electronic means. It's more equivalent to electronic warfare. I don't equate trolling (which is annoying, and irritating) with electronic warfare (which could literally kill you).
And if it isn't subjective, then what is the objective measure that you use to determine if something is "trolling" or not?
US First Amendment law is quite complex, and there's a lot of annoying little details to consider.
Essentially, designating a public forum means that the only restrictions are "time, place, and manner", and restrictions must be content-neutral. Furthermore, even the time/place/manner restrictions have to follow some level of reasonableness, with the exact level dependent on mildly arcane details, and I don't know the exact details here. The safest thing to do is say that he can't block trolls, because it's always easiest to default to assume that blocking speech is unconstitutional.
First Amendment rights are surprisingly far-ranging--it's unconstitutional for a city to deny neo-Nazis the right to march in a neighborhood of Holocaust survivors.
