Man with gun acts very silly, accidentally shoots near his willy

[Sebastian Cobb]

It's getting close to one in ten of the adult population.

That seems quite a substantial proportion to deny a supposed "fundamental right".

I don't think your characterisation of people who end up on the mental health bit of NICS as "psychotic" is particularly accurate or helpful, noting that US mental health providers have a significant history of criminally unnecessary forced admission (as ever with racial biases). (That's not my opinion, that's judgements of the DoJ in recent years.)
Or at least could obtain one if they really wanted. (Although this is true in quite a lot countries, isn't it? The UK remains unusual in how difficult it is to obtain guns.)

I think these controls only apply to shops, as far as I know there is no paperwork for private sales. Which through loopholes includes gun/trade shows.

[Zetetic]

The purchaser is still committing a crime if they're on the NICS.

I appreciate that's a different question to whether they're practically able to obtain a gun (e.g. as you say, via the loophole in many states).

Also - Does the loophole reinforce or undermine the way gun control's racial bias?
https://www.buzzfeednews.com/article/kashanacauley/what-its-like-to-be-a-black-woman-at-a-gun-show