No, the violations that you name are not okay. The Supreme Court hasn’t authorized them, and were it to do so, it would be in violation of the Constitution.
You name people who legally bought guns because they weren’t criminals at the time of the purchase. A background check cannot predict who will commit a crime in the future. Criminals don’t buy guns from law-abiding licensed dealers. They buy from corrupt dealers or from friends and family, or they steal guns:
Where do criminals get guns?
The problem with the question "where do criminals get their guns" presupposes the existence of a criminal. Criminals…
Your cited figure isn’t the number of criminals who were denied purchase. It’s the number of people who were denied. Since no follow up happened, it’s impossible to say how many were in fact prohibited and how many were false positives.
I don’t see what my feelings with regard to a shotup street sign has to do with anything.