You've got bugles, saxhorns, alphorns, saxophones, euphoniums, a zillion varieties of horn and maybe reeded horn, in allll kinds of sizes, reduced to a standard-ish selection for a particular era of western European music. What are the lines between these things? Fuckin' arbitrary. In context composers would pick what they thought people might have access to (or as a 'watch this, this is for THAT weird fuckin' instrument), or because there was a standard set for a particular military band
So why are the categories what they are? Barely consistent mutual agreement.