The answer as to "why" might lie in a better description of the dive shop itself.
Insistence on a specific configuration comes from one of two sources, sometimes intertwined.
1) "Sell what's in the wagon" is an old sales mantra. This is what's in the store right now, it is therefor the best thing for your customer. Console rigs are a simple, understandable package for most every new diver, they fit the needs of most new divers, it comes in a package, less moving parts, usually a higher profit margin. Split fins, orange or yellow lenses, and any "dive" knife in the display case.
2) "Religion", as in the drinking of the kool-aid. A certain guy-club mentality can easily shape the (seemingly heartfelt and honest) perception of the sales staff. Maybe it's like those spinning hubcap cults- it had to start with somebody cool. Yoda/grasshopper, Be Like Mike... that kind of thing. This can work to either extreme, note brass SPGs, side slung or die, Titanium Whatever, two masks on a pool dive... and the other extreme being: snorkels forever, tables- no computers, Spare Air, BC- no wing, DIMW (Do It My Way, a.k.a. Dimwit methodology, codified & diagrammed).
Religion has it's own subset: I bought this so it's the best thing ever, you need it, too. This also applies to dive vacation destinations and trip reports. We are all hoping for post-facto positive reinforcement of our choices, no less so than pre-purchase, but in a different manner.
Do whatever you want, what makes you feel comfortable... but know this- your needs will change- and if you have a brain... your perceptions may evolve. Do not get locked-into the same stonewalling that you are now noticing. Obstinate behavior is insidious.
