Yes, constitutionally, the Obama campaign's actions are not in violation of the First Amendment. But when you start denying reporters access, they tend not to like it. The action taken by the campaign was arrogant and was certainly meant to deliver a message. By the way, the press cannot "do what ever they wanno do." They have laws they must follow like everyone else.
Also, in a larger sense, the government does exercise some control over one segment of the media: broadcast television stations are granted licenses by the Federal Communications Commission, whose members are appointed by the president. Past administrations, notably that of Nixon and maybe Johnson, considered using the FCC to "get at" unfriendly networks, who owned and continue to own local broadcast stations. I can see overzealous members of any incoming administration at least considering the same when coverage is not to their liking.
I found Biden's blow-up recently when he was questioned by a veteran Florida TV reporter very telling. This administration is gonna be very "in your face" toward the media, and that attitude frequently comes back to bite you in the bottom.