They think by removing the filters and relaying all the trash around, smaller miners will have a better chance competing with big miners, who offer out-of-band services like slipstream or decide against network policy to mine trash relayed to them regardless. They hope that by doing it small mines will have access to the same TX and are not disadvantaged by blocks relayed to them where they need to fetch the transactions because they filtered out those transactions in the first place (SPAM).

Unfortunately, this is a problem created by minor centralization in the first place and will only deepen minor centralization. A healthy filtering peer-to-peer Bitcoin network will punish those big miners by slowing their trashy blocks propagation through the network and rewarding honest miners who follow the same mempool policy as most of the nodes.