Of course there's something you can do: you can enforce stricter consensus rules. But no one in the puritan camp has the conviction to do so.
Discussion
Bitcoin needs to be openly hostile to spammers and scammers. A consensus change is not necessary to accomplish that.
there's no such thing as spam
yes, a consensus change would in fact be necessary
Your choice of hostility as a strategy is noted: but how do you measure the effectiveness of the strategy? At what point do you cede that perhaps a different approach is necessary?
The effectiveness of the strategy may be immeasurable but it is the only viable option. Bitcoin is slowly becoming centralized. The only options we have to core making changes we don't like are to run an old version of core or run an alternate client. Refusing to upgrade is fine short term but long term can be problematic if there are bugs in the software. Mining is centralized but datum and ocean are making it more profitable to decentralize. If Bitcoin is going to continue being what it was created to be we must push back against bad ideas. Even if it fails, is it not worth the fight?
So go ahead and make an alternative client. Not just change a few settings in core and give it a different name.
core should exactly mirror network consensus. anything else is irrational. there is absolutely nothing core is doing that is against the rules of the network. if you don't like the "spam" transactions then convince miners to fork. in the meantime your mempool filters are about as helpful as homeopathy.
Mempools have always been more strict than consensus, nodes set the rules for the network. That's how Bitcoin has always worked. A fork is unnecessary and stupid. Miners deciding to break the rules set by nodes and route around them is a miner centralization issue. Datum fixes this.
Fork it, then. I've said multiple times here that we should be forking the fuck out of it. I'm in the puritan camp. Prove you mean it. But you don't mean it - you specifically want to attack bitcoin. You're not interested in attacking something inconsequential. Big talk, but that's it.