I do not know at which stage Wasabi Wallet (whilst owned by zkSNACKs) allowed external coordinators to be selected
Peter Todd and other developers were already saying that if some people weren't happy about the trade-off zkSNACKs took, then they could start their own coordinator. I'm not very technical, but I believe users could already change the coordinator in a .config file.
but the idea it was wrong for any member (you did not mention names) to advocate others to stop using Wasabi Wallet as being technically wrong is a debate that will be about matters of opinion.
If any coinjoin service uses/employs blockchain analysis, they should not used.
Or perhaps, just don't use that coordinator.
¯\_(ツ)_/¯
Average people with zero technical knowledge could not start their own coordinator and even if they had the skills to do so, they would not keep their service open indefinitely if there was a lack of traffic.
That's a different topic for a different debate, but OK.