TFA is "the fucking article."
It's derived from RTFA - "read the fucking article," something said when someone makes a comment that is addressed in the article. However "TFA" doesn't have the same rudeness that "RTFA" has and doesn't imply anyone didn't read the article.
For those of us that like to read and think and then comment, it can be frustrating talking with people who are just gratifying their ego by putting out words with no idea of what the topic even is.
But paying a consultant to consult for you doesn't become a bad thing to do, even if you are a bad person.
Like, consider the opposite question: Why should expert witnesses, people who have absolutely no connection to a case beyond a level of expertise in some component of it, _not_ be compensated for the time it takes them to prepare their testimony? This isn't an employee of the city; imagine you're a construction foreman and you're asked to appear as a witness to describe your experiences on a typical job site.
Why should you not get paid for preparing and giving your testimony?
By who is the question.
That's the whole point of the second scenario. And the article you are commenting on.
Why some people think that others want to hear their opinion of things they don't read is beyond me.
The second scenario you describe is clearly corrupt, but I don't see how paying a consultant for their time is the objectionable part; when you stack that against a DA on the take, a police force on the take, and a rich man fabricating evidence, that all seems like a larger problem to me than "the rich man can pay an expert to testify about their expertise", especially given that the testimony of the expert witness can be challenged.