Why? It makes perfect sense. It's not the primary. That's it. The master slave means the same thing. They are just labels in a replication state machine (or system), you need to know the precise meaning behind them anyway.

Maybe Leader Follower is the best (zookeeper and kafka uses it also usually any distributed system, that has dynamic election).

Kafka is multi master. All nodes are taking both reads and writes.

The topics are leader-follower though, no? (And that's the consistency unit, that matters.)