What you say about "your country" kinda legitimates anyone saying that about "their" country, too. There's plenty of arms dealer selling to all sorts of sides, are there not? And generally speaking,
at best soldiers defend against invading soldiers, at worst they are invading or "just" murdering some or a lot of civilians.
Remember when the cold war ended, for a while, but military budgets didn't exactly collapse? Isn't that "funny" how that works, and how we have no problem realizing that in other contexts.
https://en.wikipedia.org/wiki/Rebound_effect_(conservation)
You make war profitable, you will have more war. The details are trickier, sure. Slogans aren't enough. But if you don't even have the will, don't worry about finding a way.
> I doubt they would be happy to live in a world where the U.S. has a weaker military than countries like China or Russia.
Yeah, nevermind the big nations all having their go at weaker nations, and the US wars of aggression, under exactly that pretense. No, it's really that the every last person in that huuuuuge industry -- shoveling tax dollars into gadgets that can be used to defend, to destroy, to enforce resource extraction as well as for domestic control -- wants to look out for you, because you have the same nationality in the passport. It's the children on non-Americans that get labels like "fun-sized terroris", American children have names. Those lines could not ever blur.
Yes, you can't just unilaterally disarm. But you also can't keep hitting others (and yourself) while gearing up even more, at increasing rate, while subverting self-determination of others and intellectual honesty of self at every corner, and then say "it just happens to be a dangerous world, I'm just reacting". The people you're just reacting to say the same thing, and the people who sell you and them that lie laugh all the way to the bank, and should there be need for it, they won't share their bunker with you. They'd sooner share it with Russian and Chinese war profiteers, so to speak.