This is what Maxwell had to say in full context. The point he is making is that you don't want to incentive alternative relay networks. Nodes, core or knots or otherwise, will still validate and relay valid blocks with valid transactions in them. But it hurts decentralization if you're validating mined blocks that have lots of txns that were never in your mempool.

Big miners can profit more from these alternative txn relay networks and if you push profitable use cases to these alternatives simply because the public default relay network is too restrictive, then that is far more harmful than the alternative.