This how it's been done for a very long time. They don't use one or 2 people, it's facts corroborated by many "anonymous" sources (to us, not the reporters) all with the same story. These sources also provide the journalists with ID, verifiable facts and some anonymous sources who provide these will have more clout than some low-level staffer. Many sources are high-level or senior staffers.
Newspaper establishments like NYT, WAPO etc don't run with weak shyt. They've been reporting bombshells all year and Trump and his people have been in disarray, how many peeps fired?
What happened when Veritas tried to install a fake story with a fake "source"? Got
shutdown.
You can cry about it all day every day if you want.
If Trump and his cronies think it's BS they can sue, but as
Trump said the leaks are true, the news is fake.
SPJ Ethics Committee Position Papers - Society of Professional Journalists