Felons made their choices and the rules were available and clear beforehand.
Re: the OP
Checking the buyer only is a nice idea but unenforceable and so pointless. Think it through.
Universal background check in any form would require registration of everything, including all existing guns. By Scalia's own opinion, Courts are very unlikely to prevent it.
So what? Registration is nothing to fear. It's not infringement and it doesn't make confiscation more likely. If the gov't does get the power to confiscate they'll have the people and courts behind them - and it won't matter what is or isn't registered. At that point the game's over and lost.
I cannot see a compelling objection to registration, or to a national non-expiring FOID that includes a background check and training first.
And then a required check that the FOID is still valid, and registration, for every transfer - a simple phone call would do it.
All of this would be a one time minor inconvenience, but it's not infringement.
I do see that such a scheme, over time, can reduce the number of guns in the wrong hands, in untrained hands, or in impulse driven hands.
Guns are by far the most dangerous, lethal objects commonly available to the general public, and among the most easily and commonly misused, too often with tragic results.
Exercising our right to own them should a considered decision, and preceeded by some minimal show of responsibility.
[I posted a version of this in Legal but Ettin shut it down before I could respond to the expected vituperative answers.
Be polite, make your points and I'll try to answer them.]