I get that Taylor’s show creates the illusion of her singing the songs, and that offends you because it is just an illusion. But folks are paying for the event. You aren’t getting upset over her using stage makeup and effects, nor the myriad other ways in which the production creates “spectacle through illusions”.

Swift is a singer and the main point is to hear her singing. The other stuff is to enhance the overall experience, but if she cannot deliver on the main attraction then I would consider that fraudulent if there was the expectation to hear her singing live. You're right, though, most people paying thousands for tickets to her show only care about the event i.e. being there.