The problem with P@H is consistency.
Sure, there'll be a few stores around that happen to have knowledgable, caring staff - but I think that's more a happy accident than due to any particular hiring policy from management. P@H are in business to make money, pure and simple. To make this money, they're not going to be able to pay their shop floor staff too much money, therefore it's going to be staffed by a lot of people that aren't really experts in the field. Jobs in places like this are fairly easy to find, so they tend to attract a lot of college/uni students, people that are just looking to earn some money and so on, rather than dedicated career types. This is unavoidable, and also means staff turnover will be relatively high.
The upshot of all this is that it's impractical and unrealsistic to put all the staff through the rigorous and lengthy training required for them all to become the experts we'd all like them to be. So it seems that instead, they've developed a few policies and rules that, while they may seem bizarre and stupid to people that know better, do actually help to prevent people new to the hobby to make mistakes, and are easy for the staff to learn and enforce. Surely that's a good thing?
Personally, I'd like to see rules such as this applied more rigourously at all P@H stores (and in fact, a lot of other LFS) - with the one caveat that, if you disagree, there should be someone around that does know what they're talking about and can make a proper decision.
I'm not bashing P@H here (although to be honest, I prefer to buy my fish elsewhere) - I'm just trying to point out why they do what they do. It's the business model they've set that allows them to make the most money (and nothing wrong with wanting to make money - the benefit to us is cheap prices on equipment etc!), and isn't without its drawbacks.
You can see this sort of thing in most retail sectors - I used to work in IT, and had a hobby of going into PC World and asking their clueless staff about complex stuff, just to hear their answers. I got some right howlers from there!