I'm pretty tired in general of the popular certainty that legitimate researchers come up with whatever results their "corporate masters" pay for.

Of course it happens.

However, professional journals exist to review and essentially cross-examine any papers that are submitted to them, to keep bogus or slanted "findings" from appearing. This process usually works, though once in a while something fraudulent slips through.

If they suspect fudging of data, or outright deception, rival researchers with advanced degrees try to ferret it out, both to further their own careers and to get at the truth.

Professionals adhere to professional standards. I think the notion that all experts are bought comes from a number of places, including:

the phenomenon of "expert witnesses" in court,
unfamiliarity with the research and publication process,
absolute faith in one's own prior beliefs,
a failure to understand the difference between fact and opinion,
and an expectation that most researchers lie for cash.