There are two immediate problems when people tell you what you do and don't need in regard to self-defense or home defense.
One is that, it's baked into the reality of everybody who owns a gun for defensive purposes that we aren't choosing the fight. We don't want the fight. We never agreed to any terms. If somebody breaks into my house, I don't know if it's one unarmed junkie or five thugs with guns. Hell, if a white cop shoots a black man in my neighborhood, it might be a full blown riot.
Making any claim of what one needs to defend him or herself is claiming to have some pretty perfect knowledge of events that haven't happened yet.
The other thing -- and this one really bothers me -- it tells me that you're expecting the victim, the person being attacked, the person who didn't want the fight, the person who didn't agree to the fight to take on the burden of making the fight fair.
The attacker is never looking for a fair fight. The attacker is looking for a victim. When you're lecturing me that I don't need an AK for home defense, what you're saying is that, if a dude breaks into my home with a pistol that he's ready to use, it's not fair for me to greet him with the muzzle of an AK, and therefore I shouldn't do it.
When we talk about proportionality in self-defense ethics and law, no sensible person is going to define the terms of proportionality to put the burden of the person being attacked to evenly match the weaponry of the attacker. Proportionality is the evaluation of whether the threat is deadly or non-deadly. If it's an imminent deadly force threat, then you're justified in using deadly force in defense. The deadly instrument doesn't matter, or shouldn't matter, ethically or legally.