The citizens will have artificial robots too. Or do you think there's some reason why AI shouldn't be protected by the second amendment? Either AI can be weaponized - in which case it's protected by the second amendment - or it can't, in which case there isn't a threat from it in the first place.
I'm not ideologically opposed to what I think you're saying, but it is actually the case that many weapons are not allowed to be owned regardless of the second amendment. Nuclear weapons, for example. It doesn't matter if you build it entirely yourself using completely novel processes not owned by anyone, and acquired all inputs legally, it is still 100% illegal for a private citizen to own a nuclear weapon.
There is no legal reason why AIs couldn't be governed under the same principle.
You think the government is going to create an ai military to kill millions of civilians without being overthrown by the other hundreds of millions of armed civilians in this country?
I think the question is more, will there be a country somewhere that emerges as an AI/robotic super power.
You shouldn't just be worried of your own government here.
And the other issue is, why would the post-revolt government/businesses abandon AI/robotics?
The truth is, this won't happen over night. People will have less work over time, be paid less and less, the gap between classes will grow bigger, etc.
I guess another way to put it, take a country like India with lots of unemployment and high corruption, I don't think if they had guns they'd all revolt. You have to believe there's a point to revolting, an alternative that's better and worth the risk.
This is ironically a simple issue of demographics. Whether the biological humans like it or not there will be a larger demographic of artificial entities that do more of the economic and military work and therefore will have more weight in all things political.