I read this post yesterday, together with the one from Peter Wuille on the mailing list it was the most interesting reply I read. I didn't know there were miners who were offering to directly broadcast their non standard transactions through their web interface: https://slipstream.mara.com/

Also his findings show that spam filtering in the end is detrimental to a healthy P2P network. This was something I was not aware of as well, I thought filtering would genuinely impede transactions from getting into the network. I didn't know also about Libre relay also which voluntarily takes the counter side of Bitcoin Knots.

To me this is a strong argument against spam filtering. Ultimately it looks like we will have to deal with non-payment data on the network. From a utilitarian perspective I still struggle to see why using Bitcoin would make sense for other use cases than money though.