No, it is ethical to have weapons because it's a bulwark and disincentive against countries with even more tyrannical objectives. This is not to defend the extent to which weapons systems are being invested in. But they need to be invested in. The race is not optional.

It's a bit more nuanced than that. From a practical perspective, China and Russia's possession of nuclear weapons has been a sufficient deterrent to US or NATO action for nearly a century. By contrast, The advent of smarter bombs, stealth technology, and drones has largely freed the US from the negative consequences of large scale bombing campaigns and ground invasions.

The result has been 3 decades of near continuous warfare in countries of little strategic threat to US interests. As a peer competitor to the US, do you fear a smarter drone or an ICBM?