Redis is no longer free and open source software with this move. It is now proprietary software.
RedisLabs developed proprietary sharding and scaling capabilities for Redis. Best I can infer, they want to open source the module, but not compete against themselves if others get into the Redis cloud hosting business.
Now you might think that commercial use is a small semantic detail. But it is one that the open source / free software community has always insisted on, up to and including left-loonies like Stallman.
Of course none of this means that it is wrong or unfair of RedisLabs to do this. It merely means that what they are doing is not open sourcing anything.