You two seem to literally lack an overall knowledge of things.
We still produce swords and bows today, don't we?
A mass of people still practice with swords and bows today, don't we? It's tradition to learn how to utilize such things, even without war. Why? Because it's honorable, it's fun, and its challenging.
Why did they choose NOT to make better weapons? Have you ever heard of live for the hunt? You can't really live for the hunt if you just shoot something with a gun. Some can, but it's more fun for others to utilize things such as Bows, it's more challenging, and traditional.
While things such as Ballistae may no longer be produced for no needs; things such as swords, staves, knives, etc, can be used in a more traditional sense.
Siege Weapons are NOT still produced today.
As for their swift advancement in technology, war isn't the only thing that can inspire a massive race of tech. Neolibre's were ones to love chronicling history, exploring, and developing new means to do so. They did so swiftly and efficiently, with all intentions to finish their goals.
While a mass of technology borders 1970's America, they can easily advance from a pre-industrial society, to an industrial one.
Just look at our world for example. Back in the 1900's, we were fairly primitive with technology. And as the years progressed, their was a big boom in technology advancement. Sure, it was due to war, but you're basing your ideas based on what happened in our world today.
You tend to forget this is technically a science-fiction setting. It's a whole different ballgame out here, people can advance more than Earth quite easily.
Did you know, that if the Dark Age's on Earth never occured, we'd probably be more advanced than we are now?
In the fifty or so years that Azura had in peace after the war, they used the powerful catalyst of gaining knowledge to develop technology to achieve such.
But like I stated, its primitive tech.
Back on the answering of the questions...
Like I stated, rocket fuels and the like do NOT need to be expanded upon through means of destructive forces. They CAN be produced through different means other than weapons. I don't understand why you tend to think it's the only way. It. Is. Not.
They "Selectively" did not develop guns, because they were not needed. The concept of the gun never came to them like it came to us. They were a honorable, traditional society that wanted to know more of their world. They had no NEED to develop weapons. Guns kill quite easily. One shot, and you can die.
Yes, they also increased their ways agriculturally. Domesticated animals, commerical crops, etc. Azura is a very lush planet; they do not waste like humans do. They use their non-renewable resources sparingly; and their renewable resources no more than they need to. They keep their pollution to seperated areas.
Also, it's quite easy to manage a 1970's society when that society is not directly based on the 1970's, but is generally framed in that technological area, plus/minus things.
You tend to forget Azura is a place of peace, pacifism ideals. There is little crime on the planet, but the Neolibres are quite capable of defending themselves, based on previous upbringing in the past, and traditional means of raising the young.
Sure, they may have police taskforces with swords, or night sticks; but that's about it. They can do quite well in helping keep the peace.
Please keep in mind, Uso, Rei, that not exactly everything has to be mirrored off of the development ways of the Earth.
If it was, what's the meaning of Sci-Fi? The meaning of Fantasy? Fiction overall?
Edit:
Nothing personal, Andrew. We're just trying to help you get this right.
I know, and I highly appreciate such.
I'm just trying to counter the questions and explain as much as I possibly can in a different point of view.
If you think you can come up with better means to alter such in a good way, that would be great. But I still like to defend my creation as such.