Filters can still be run. You are free to run whatever relay policy you want. The network is better off if the relay policy is in close alignment with what the consensus policy is so the defaults shouldn’t be filtered so far below consensus.

Op return exists because it is less damaging to the chain than the alternative methods people where using which cannot be stopped. Spammers don’t care about your virtue signals. Pretending that one large op_return is worse than many utxo bloating alternatives from a legal or moral stance is retarded.