I played the Final Cut on Steam last year and I was completely blown away by it. Ended up as one of my favorite games of all-time. The writing was incredible to me -- humorous, thoughtful, and surprisingly moving at times.
I wish I could play it again for the first time.
Part of that really comes down to how the Salamancas viewed Gus - he was just the gay little chicken man - and now his was unarmed and without his protection, so there was no perceived threat in that moment. Obviously a fatal mistake, but one consistent with the characters IMO.
Gus leaving the gun down in the lab is the equivalent of a normal person keeping a gun in the nightstand. Obviously you're not planning on having a shootout in your bedroom, but you want to be prepared in case the worst happens. Gus knew Lalo was looking for the lab and that he'd eventually find it the longer he evaded Mike and his men -- and he sure as hell wasn't going to let himself get cornered down there with no way to defend himself if worse came to worst. Seems logical to me.
I'm sure the totally-not-fascist authoritarian government Icono so desperately wants is just going to overlook not only his ethnicity but also his history of drug use and homosexual acts when they're deciding who gets to benefit and who... doesn't... in their society. Totally nothing for him to worry about, no sir.
All of that should've evaporated a month or so ago when he spent the day railing against welfare queens only to admit he was mostly just trolling because he was bored at work a 1000 miles from home.