I’ve caught some grief for this, right here on this forum,
I can see how you've caught grief here for that. You're going to get some more.
Grief:
An FOID tells you nothing about motive; it only tells you about arrest record up to the time of issuance. Every single repeat gun-crime-felon in Illinois, at one time in their life, had their first felony. Prior to that, they could get an FOID. Besides, those with bad motives that would qualify for an FOID don't go to gun stores and most FOID-based purchases would always be for gun stores.
Since nothing known to man could ever peer into the mind of a gun buyer to get their motives, we can only base decisions on physical evidence. The physical evidence that tells me they're eligible to buy a gun is that they're not in prison or jail. Now, if I know that they had been, I'd be happy to refuse to sell to them but the problem there is not whether I can tell they're dangerous or not, the problem there is that the state let dangerous criminals out of prison to prey on society.
And if a dangerous person has been released on society and I refuse to sell them a gun they can either take the gun from me forcibly or get one somewhere else. In any case, a person who wants to do bad stuff doesn't care about laws requiring FOIDs to get a gun.
But if it’s just a little bit harder for him to buy ammo, it may mean one less murder or one less robbery. So I can live with a little inconvenience on my part if one less felony takes place.
Well, if murderers spend all of their time murdering then any time we can distract them for a moment does actually prevent a murder. But, assuming murderers spend time doing other things and only murder for a couple of seconds at a time, no inconvenience will even slow them down.
You don't live with a little inconvenience; what you live with is the means by which the state of Government can identify gun owners at worst. At best what you have is simply a completely ineffective and costly government program that does nothing to reduce or prevent crime and distracts those accountable from doing what they really need to do.
Gun laws don't work. Look how well FOID cards are working in Chicago:
http://www.huffingtonpost.com/2013/07/07/fourth-of-july-violence-c_n_3558463.html
So there are a couple of arguments that I hope you can see for why you're wrong.