In the case of
New York Times v Sullivan Scotus ruled in 1964 that a public figure can sue any media under two circumstances:
1). The media organization presented something it knew to be false and therefore acted with malice;
2) The media organization presented something in a reckless disregard of the facts.
If Trump could prove his case and if he had lawyers who believed in his cases against MSM only, Trump could be in court right now with dozens of suits filed.
However, instead of Trump pursuing in the courts his dozens of beefs against MSM only, he's working daily with Stephen Bannon to destroy the MSM.
Trump is not serious about reforming or improving MSM. Trump-Bannon and the Dancing Fanboyz are in their high kicking chorus line out to dismantle MSM completely and entirely.
No surprise given Trump has also targeted the courts and the Judiciary. Trump doesn't like or trust them either for reasons we well know also.
New York Times Co. v. Sullivan 1964
Held: A State cannot, under the First and Fourteenth Amendments, award damages to a public official for defamatory falsehood relating to his official conduct unless he proves "actual malice" -- that the statement was made with knowledge of its falsity or with reckless disregard of whether it was true or false.
https://www.law.cornell.edu/supremecourt/text/376/254
The legal means have been in place for several decades but this is not what the Right Sector and their hero duo Trump-Bannon are about.