Filtering spam is also censoring. Now the censoring is present, it's waiting for the next thing to censor. Maybe transactions that use too much co2, that are not inclusive? Sounds absurd, but I would not be surprised.
Discussion
It's not really censoring. You are free to route or not route whatever payments you like on your own node. In the same way you are free to delete notes you're not cofortable with hosting from your nostr node. The network is free to route around you (and probably will).
Filtering spam is not censorship.
Saying that filtering spam is censorship is like saying water doesn't wet.
The definition of spam in bitcoin is clear and simple: any transaction that is not a monetary exchange and harms transactions that are monetary exchanges, for example by slowing them down.