A clean mempool is desirable because it keeps your disk space ready for better uses than storing other people's spam Regarding your syllogism, your first premise fails of configuration options have any other purpose beyond keeping data off the blockchain. And they do: the primary purpose of mempool policy, for example, is to police your mempool, not your blockchain.

The teem "ineffective" in your first premise provides a clue to its faultiness: it embeds a negative into a key term, and when this term is unpacked, we discover that you are really assuming a universal negative: namely, that there is no other purpose beyond the one you identify as ineffective. Proving a universal negative is, of course, really difficult, and a semester of philosophy might teach you this.

Do you really prioritize fleeting ram use over permanent disk storage? That is a silly priority to have.

Ram is more precious than disk space, that's why 1tb of ram costs way more than 1tb of disk I prioritize efficient use of the scarcer resource

I prioritize eternity over fleeting.

You clearly don't understand cost and the multidimensional status of things. There's more than just one kind of limitation.