Yes, you can always find some fool on YouTube who doesn't get economics.
Yes, there is tax on tax, but you pay tax on your earnings before you get it.
So it is tax on tax on tax really.
Fuel price competition is limited by lots of factors, but as the number of competing suppliers drops, there is less opportunity for small retailers to compete by bringing prices down.
The supermarket filling stations are being bought out by venture capitalist scum.
The remaining supermarkets no longer have to run at minimal margins to attract shoppers to their sites (where other sales will bring in margins).
To some extent, this is good news because it is now possible that the bigger margins will allow new entrants who might actually compete.