Right that's a downside. As I said I recognize the downsides. The upside is that transactions that don't follow the default policy are rejected. That's the efficacy of the OP_RETURN cap. I want certain transactions to be rejected from my mempool, the cap does that with great efficacy as you stated yourself.
Discussion
I did not say that. It rejects them from your own mempool but once they are mined, you have to retrieve it from other nodes that know that transaction.