If filters do not work at making it more expensive and making the lives of spammer more difficult. Why the very dev that wants spam post this article explaining why they work at making spammers endeavor costly and difficult? https://bitcoinmagazine.com/technical/the-bitcoin-mempool-relay-network-dynamics

Other misconception: node should follow miners' relaxed node policy. Nodes are counter power to miners. If the network filter policy is stricter, mining spam would lead to slower block propagation. Thus probability of getting orphaned by an honest miner propagating faster. Strict filters forces pool to mine honest tx and follow what policies the majority of the network enforces.