That’s because (IMHO) AR-15’s suck.
I’ll put my Saiga (that I lost in an unfortunate boating accident) up against it any day.
IMHO, the AR15 is a fine choice because it is chambered for the same cartridge that may be used by our adversaries in the coming unpleasantness. Remember, your civilian weapon is only useful as a means to procure a military weapon. Unless your Saiga is a class III weapon and you’ve got buttloads of ammo, mags and spare parts, you’ll be handing it off shortly after hostilities begin. Saiga ammo and magazines won’t be much use in an M4, but AR ammo and mags work just fine.
That’s crazy.