Joshua Jones
When all is said and done, all's quiet and boring.
You are absolutely right that it is weird; military tradition is a strong force in nearly every military, so weirdness is often preserved. USMC dress uniforms still include sabers, for example. But this is what gives them inspiration and a connection to their past, a "brotherhood through the ages", as they often say.It's all good. I was just trying to point out that there is nothing natural about the common military rank structure - it is actually pretty weird - especially in egalitarian societies.
I'm sure that the OP has some much larger fish to fry before this stuff matters. It's just interesting to talk about.
And, I am sure you are right that the OP has bigger worries than this. I am a bit obsessive in my world building; I spent 8 years developing my universe before I made a single character, so I tend to overengineer things. But, if the military aspect is going to be a significant focus, it may be worth expanding the backstory (assuming he/she hasn't already). But, if they aren't a major part, then I wouldn't worry about it, and I would just throw in some ranks and move on with life.
Really, it all depends on what the OP wants to do with the story.