This whole argument about increasing block size is irrelevant here because the adoption hasn't increased and legitimate usage of this "payment system" is not higher than the current existing capacity to require a capacity increase.

Right now there is a mempool congestion and fees are high only because of the ongoing attack so the solution to that is to prevent the attack not increase the capacity to store more of their spam transactions. After all Bitcoin is not a cloud storage so that we increase the block size so that these attackers can store more of their arbitrary data in its blockchain.