"I think anyone will agree that FDA's intentions are good."
I don't entirely, though I'm not claiming malice either. The purpose of drug testing is to make drugs safe. The FDA has mistaken goals for means, and now they are testing drugs for the purposes of testing drugs.
If an untested drug has been used for decades by millions of people to treat a chronic condition that requires each of them to themselves consume the drug for decades at a time, that by itself puts such a sharp, strong bound on the maximum damage the drug may be doing that it is well in excess of what any study could possibly hope to establish. The improved methodology the study may have is simply swamped by the statistical power of a sample five or six orders of magnitude larger (measured in man-years) we have in the real world. In fact you just don't get any statistically more powerful than a "sample" of 100%.
Even if the study managed to produce some small negative side effect there is no chance in hell that it will exceed the positive value of a drug for gout.
I've actually seen this before. Several children's drugs have been "unrecommended" by the FDA for toddlers, not because they could produce a shred of evidence that they were dangerous but because the studies-for-the-sake-of-studies had not been done. Again, decades of use by millions of people dominates what any study could produce.
(By the way, when I say "dominates what a study would produce" I emphatically do not mean "is perfectly safe". I mean precisely that a study will not be able to find the small damage. Drugs have after all gotten all the way through our stringent approval process and then had to be pulled because it turns out they were still dangerous. If the process couldn't catch the several diet drugs that turn out to give you a heart attack, it isn't going to pick up on something that could escape hundreds of millions of man-years of usage. Studies do not have infinite resolution.)
It's a continuing degradation in the standards of science, as the disease of scientific form replacing scientific substance marches on. That's why I don't claim "malice" in my first paragraph. Malice is not required, merely the raising of form above substance. I do not call "intention to have good form even at the cost of substance" good intentions.