Captain Seafort wrote:How, exactly?
How? You claimed that there are no officers in the department because O'Brien was in charge... because there were no officers.
Captain Seafort wrote:If I was trying to claim that there were no Ensigns or higher-ranked personnel in the staff and that O'Brien was Chief Engineer you'd have a point, but I'm not.
You're claiming that there were no officers, and we know that O'Brien was department head. I fail to see the difference.
Captain Seafort wrote:the rank structure is identical to that of the US Navy
The rank structure certainly bears a resemblance in its naming convention (which may be, BTW, simply due to translation from "UFP standard" to TV English,) and in general there is deference to those of higher rank; however, we've seen an ensign as dept. head and an enlisted man as same. If the USN doesn't allow for such things, I'd say that's evidence that there are differences rather than an implausible claim.
Captain Seafort wrote:I'd like to hear a reason why a hierarchical ranks structure is in place if it isn't used to determine who defers to whom.
Who knows? Who cares? As I mentioned above, we have an ensign in charge of ops, we have an enlisted man in charge of engineering - canon. It's a lot more logical to say that these things are allowed by SF's structure than to say that the entire engineering staff of a Fed-administered station has not one officer... especially considering the previously-shown ubiquity of officers in SF, and the commensurate paucity of enlisted men.