I dunno, it's just been one of those Traveller bugaboos that's been with me for quite a few years.
BG,
It's a case of cultural blinders.
When first clapping my eyes on
Traveller and the setting which slowly accreted around it, I couldn't quite grok the "militancy" of it all. Sure, it was a game and a game is going to play those aspect up, but why would people be running around in ships like that let alone selling them to anyone with the loan papers?
Then I began reading more and more about the historical periods which
Traveller's interstellar communications most resemble and I realized that there was a
very fine line between trading and raiding. What's more, even the best intentioned traders couldn't depend on the intentions of others. Ships in the service of the EIC, for example, were armed nearly as well as those built of the Royal Navy.
We've got distant central governments whose forces are generally pinned down protecting important systems and a helluva lot of "back country" where, when nastiness occurs, it's going to be months before any central government officials hear of it.
Shopping for Cessnas and stumbling across a F-16 isn't going to happen, that's like shopping for Cheese Whiz and finding caviar. There are brokers and yards who specialize in each kind of craft, so you'll visit either depending on your needs.
"Commercial" warships have a role to play in the setting and enough historical analogs to make that role entirely plausible.
It's just that that role seems awfully strange to our 20th/21st Century, mass media, liberal, Western democracy eyes.
Regards,
Bill