General Discussion

"...the Federal Communications Commission (FCC) does have jurisdiction over cable, as it is an independent U.S. government agency tasked with regulating interstate and international communications by cable, radio, television, wire, and satellite, a role affirmed by the Supreme Court in United States v. Southwestern Cable Co." (Google search)
Perhaps you are correct in saying this is not true, but the Trump regime can put official pressure on MSNBC broadcast and business practices with the FTC or the IRS to target them for reprisals if they fail to follow their news content and personnel preferences. So they submit and find it easier to fire reporters like Mr. Dowd. But in the long run, such appeasement will only be met with demands for the abject surrender of all journalistic independence and the "Fourth Estate" will wither away to nothing but the PR organ of a despotic regime.