Using the word 'tax' here is like calling anything that you need to pay for 'tax'. If you put a bit of money in a vending machine to buy some chocolate, you don't call that vending machine tax, do you?

If you were to scope it to 'services' or 'platform', then perhaps we should call virtual hosting cost not cost but tax :p and if you rent a movie, that'd then be movie tax, or rental tax? But what about actual tax, are we going to call that tax tax? Because at this point people just start using the word tax for every generic transaction.