TLDR: it doesn’t actually matter.

What goes into an individual’s Mempool is just deciding which tx are propagated by that particular node, but what actually gets mined is all that ultimately matters.

Running Knots is more of a matter of principle, rather than a choice that has any effect whatsoever on what eventually goes into blocks. It’s a moot point. To each their own node, but running knots does literally nothing to fight spam. It’s just someone arbitrarily deciding what’s ’legitimate’ or ‘illegitimate’ rather than allowing the free market (fee market) to decide.