I agree with you to some extent. Let me clarify 3 points:

1. This policy applies at the pool level, not the protocol level.
2. Some pools currently block transactions using undisclosed filters, it is not a technical challenge to do so with the current software
3. QoS manages priorities; it doesn't prevent transactions from going through at some point

If this system becomes a standard solution that fixes the congestion issue, dishonest pools can't use censorship as a pretext for solving problems. I'm not suggesting that there are currently pools engaging in this behavior, but I believe the overton window has been opened.

rblb

bitcoin

Transaction QoS? Why is this not a thing?

If you have such 'priority mempool/blockspace' feature done, we are in a "one small PR away from censoring unwanted actors" situation.

I'd like to have as much friction as possible for adding censorship to bitcoin. This would be an incremental change toward adding censorship to bitcoin.