In Kafka, multiple consumers can recieve multiple partitions. The only thing, from a consumer's perspective, that's special about partitions is that it's the level at which message ordering is guaranteed.

That's exactly the same semantics provided by RocketMQ's "message queues", from what I can tell - except perhaps that these message queues are explicitly subscribed to? If that's the case, you can do that in Kafka too, but it's generally discouraged, as it can lead to performance problems.