...even if the blocks are full with bogus transactions.
Please provide a definition of 'bogus transaction'. Without such, I am unable to understand your argument.
A very simple or simplistic explanation:
If I want to buy something, I need to pay. That's a valid reason for making a transaction so that transaction isn't bogus.
Now, if I start sending dust between my wallets, in thousands of transactions, in a meaningless way (as far as real-life transactions go), just to generate spam, clog the network etc => that's plenty of bogus transactions right there.
Who do you need to pay? The miner.
I meant the seller

Does sending dust between wallets in thousands of transactions require fees? There is no distinction for the miner, pay the fee they require and your transaction is just as legitimate as any other.