[devil's advocate]
But guns are so effectively "scary"-ized that here we are. I would also mention that unlike cars there is a USSC decision affirming the fundamental right to own and bear a firearm in the home. I'm not sure that "unless you have had two beers" will pass scrutiny on that one.
I snipped, but totally agree with all your points above. I don't want the law telling me what my personal responsibility is. While that means I have to put up with jackasses that drive after downing a fifth of Jack Daniels and killing someone, or jackasses that down a fifth of Jack Daniels and then go Homer Simpson with their gun, there are laws to prosecute murder and mayhem. I, personally, don't want to carry a gun when I'm inebriated. Personal choice. I might lock it in the car in public, more so from fear of the police than fear of me doing something stupid. At home, I won't lock it up - as you say, I have a right to defend myself when drunk.
I should have that right in public too, but as I mentioned, there are state laws and they are ambiguous. I - though I hate doing so - have to weigh the probabilities of some SJW weirdo calling the cops if they see me with a gun on in a Boise hipster bar vs the probability of having to use the gun there or on my way back to my vehicle. Then I have to hope the cops who show up are reasonable, because the ambiguous nature of the law might mean an anti gun cop could arrest me for having had just one sip of beer. If they're going to have a law I don't approve of*, I'd prefer it to have some solid metric so I know when I'm breaking it.
My "one or two beers" rule is my way -personal choice - of walking that tightrope. Also my own line of where I feel I'm still good with a gun and can still go to condition yellow versus being stuck in condition white. Subject to change without notice. :)
*On the other hand, many states, even those where you might not expect it (Wyoming is a glaring example) won't let you carry a gun into any establishment where alcohol is served, let alone have a beer with a gun on. I suppose that makes the law easy to interpret, but my right to defend myself shouldn't be taken away simply because there are bottles of alcohol minding their own business within 100 feet of me. So while ambiguous, at leat Idaho's law gives me more freedom for personal defense.