Why should they relay to nodes that don't even support BIP47? SAMOURAI users are likely to use paynyms, so a "knot" not forwarding the transaction is of no use and just uses bandwidth the node/Tor-network could spend on connections that actually support 100% of the use cases.
Discussion
This whole drama still feels petty to me. Maybe it makes a little bit of sense except they could just put in a message to users and be done with it. Definitely seems a lot more like a resentful “well two can play this game” than some genuine technical decision.
It may very well be a “two can play this game” reverse attack, but I love it.