Yes, I agree, but it's not really any different to the way that various shops sell a 4 pack of Kitkat for £1 but sell them individually at 85p each. It's clear the 85p each is gross profiteering, but there's no law against it.
Or the way that some branded items are always on "special offer" at one of the supermarket chains in a carousel, such as McCoys multipack crisps or multipacks of diet coke, or certain brands of washing powder.
The Tesco club card pricing (closely followed by others) is just a new version of those old tricks.
Or contracts for broadband, sky/virgin tv, landlines, mobile phones, power, etc etc where you have to sign up for a new contract at the end of the term unless you want to end up grossly over-paying on their "non contract" pricing.
Or new car dealerships where the "List price" is a work of fiction because no one ever pays the list price for a new car.
You can't legislate for everything. The likes of DFS claiming "50% off sales" was clearly misrepresentation as they were actually lying by saying that the price was previously £x when it wasn't, hence the more recent requirements to be able to prove it really was £x for the required number of days.
Tesco aren't lying, nor are Virgin, Sky, BT, etc - that's the difference.