Why is the mainstream media routinely ignoring the illegal collection of data on Americans by NSA?

Andrew McCarthy:

During the Obama years, the National Security Agency intentionally and routinely intercepted and reviewed communications of American citizens in violation of the Constitution and of court-ordered guidelines implemented pursuant to federal law.

The unlawful surveillance appears to have been a massive abuse of the government’s foreign-intelligence-collection authority, carried out for the purpose of monitoring the communications of Americans in the United States. While aware that it was going on for an extensive period of time, the administration failed to disclose its unlawful surveillance of Americans until late October 2016, when the administration was winding down and the NSA needed to meet a court deadline in order to renew various surveillance authorities under the Foreign Intelligence Surveillance Act (FISA).

The administration’s stonewalling about the scope of the violation induced an exasperated Foreign Intelligence Surveillance Court to accuse the NSA of “an institutional lack of candor” in connection with what the court described as “a very serious Fourth Amendment issue.” (The court is the federal tribunal created in 1978 by FISA; it is often referred to as a “secret court” because proceedings before it are classified and ex parte — meaning only the Justice Department appears before the court.)
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There is much more.

To answer my own question in the headline above, I think it is because the mainstream media has a conflict of interests.  It is the beneficiary of illegal leaks of information that has been gathered by the NSA and shared with other government agencies and it does not want to stop the flow of information which it deems necessary to the coup attempt against the Trump administration.

For that reason, they are ignoring one of the biggest abuses of power in history.