I basically agree but lets look at it:

So we have a bunch of trusted third parties that issue spam filters that people apply to their mempools. there's no standard everybody just uses the one that they like.

But none of that matters at all, the only thing that really matters is what transaction the miners are looking at and they're using no filters at all because they want to get the transactions with the highest fees.

So you have a bunch of subgroups that Consciously avoid seeing particular transactions out of idealism. Meanwhile the miners just mine whatever will keep them competitive with the other miners.

See what I mean?