The claim Stallman would make (after punishing you for using Open Source instead of Free Software for an hour) is that Closed Software (Proprietary Software) is unjust. but in the context of security, the claim would be limited to Free Software being capable of being secure too.
You may be able to argue that Open Source reduces risk in threat models where the manufacturer is the attacker, but in any other threat model, security is an advantage of closed source. It's automatic obfuscation.
There's a lot of advantages to Free Software, you don't need to make up some.
I think there's a lot of historical evidence that doesn't support this position. For instance, Internet Explorer was generally agreed by all to be a much weaker product from a security perspective than its open source competitors (Gecko, WebKit, etc).
Nobody was defending IE from a security perspective because it was closed source.
Your post feels like the last generation lamenting the new generation. Why can't we just use radios and slide rules?
If you've ever enjoyed the sci-fi genre, do you think the people in those stories are writing C and JavaScript?
There's so much plumbing and refactoring bullshit in writing code. I've written years of five nines high SLA code that moves billions of dollars daily. I've had my excitement setting up dev tools and configuring vim a million ways. I want starships now.
I want to see the future unfold during my career, not just have it be incrementalism until I retire.
I want robots walking around in my house, doing my chores. I want a holodeck. I want to be able to make art and music and movies and games. I will not be content with twenty more years of cellphone upgrades.
God, just the thought of another ten years of the same is killing me. It's so fucking mundane.
The future is exciting.
Bring it.
I don't read the OP as saying that: to me they're saying you're still going to have plumbing and bullshit, it's just your plumbing and bullshit is now going to be in prompt engineering and/or specifications, rather than the code itself.