You need to back this up with some citations.
The generic drugs also do not have to have the same excipients (inactive materials used to make the final drug product like a pill or capsule). Normally this doesn't matter, but if you have an allergy to an excipient, the branded might be the only one you can take.
Finally, there have been issues with some generic drugs, namely generic Wellbutrin. The FDA asked for bioequivalence data on some dosage forms, but not the 300 mg pill. That pill released drug much faster than the branded and patients had some nasty side effects as a result. I've also heard the same with some generic anti-epileptics. Epilepsy is a disease where drug levels need to be very tightly controlled.
[1]http://www.pharmacytimes.com/contributor/timothy-o-shea/2016...
Do you want evidence that generics manufacturers fake their equivalency tests? This is going to be harder, because the FDA doesn't publish the private sector data. I can try to see what I have on hand.
Do you want evidence that the FDA doesn't prosecute these huge problems? I can only point to the routine handing out of the equivalent of "yellow cards," i.e warnings of misconduct, but still allowing repeat-offenders to sell in the U.S.