Note: Highlighted in the WAPO article the severe restrictions placed on members of the press. From WaPo (linked above):
"One restricted group will be the media, whose members will not be allowed to walk along the march route. Reporters and cameras are restricted to three enclosed areas along the route but are not permitted to walk alongside participants walking from the Pentagon, across the Memorial Bridge to the Mall."
Further, note, In general, First Amendment rights can be restricted in "time, place, and manner" if needed to fulfill an "important government purpose," as long as those restraints aren't message-based (i.e., "content neutral"). Some communication channels must remain open, and the restraints must be "narrowly tailored" to the government purpose. Here's some more info.
Finally, I don't know all the case law, but perhaps the press could make the case here that the restraints are not narrowly tailored enough. But of course it's to late.
"America was never innocent. We popped our cherry on the boat over and looked back with no regrets. You can't ascribe our fall from grace to any single event or set of circumstances. You can't lose what you lacked at conception.
"Mass-market nostalgia gets you hopped up for a past that never existed. Hagiography sanctifies shuck-and-jive politicians and reinvents their expedient gestures as moments of great moral weight. Our continuing narrative line is blurred past truth and hindsight. Only a reckless verisimilitude can set that line straight."
--James Ellroy, American Tabloid
Ensure a Free and Fair Election (Ban Paperless Voting Machines
"The basic tool for the manipulation of reality is the manipulation of words. If you can control the meaning of words, you can control the people who must use the words."