There is no need to be sarcastic. HMV and HMV.com may indeed be different in that sense but that doesn't mean anything. Many companies have such websites in addition to their shops but they work together.
So? Your expectation of the business practices of one store based on how some others run theirs is your error, not HMV’s. The T&Cs of both operations made it fullsomely clear they operate as seperate businesses with different pricing structures and no crossover between them. Your desire to conflate the two into one homogenous whole is not their problem.