Do you think "Pay to relay" is just another way of pseudo-banning users / segregating the network between those who can pay and those who cannot?
In a way it's kind of worse because it's a monetary 'ban' not for behaviour.
Discussion
Personally I like everything to be open and each user decides what relays to connect to, who to follow, block, mute, etc. That said relay operators have real world costs associated with bandwidth, disk space, etc. and SPAM and malicious users cost them money.