In that case a stronger argument would be: regardless what anyone thinks regarding inscriptions (if they are spam or not) *everyone* should agree that those who see them as spam deserve to have the option to not relay them, even if it has to be turned on manually.

In my view, arguing that "nobody" tweaks their configuration file is anti-bitcoin thinking. Running a node is all about sovereignty. Having yet another option (there are many) for filtering unconfirmed transactions empowers the node operator to enact his own mempool policy. Conversely, arguing for not adding these options goes against the bitcoin ethos.