Ah yes, I went through the announcement and missed this sentence, thanks for pointing it.
Makes sense as well, since "commercial licenses are also available from MongoDB, Inc." (https://www.mongodb.com/community/licensing)
Not a bad thing for MongoDB. I think Atlas was the only managed service after they bought mLab, it's good to have options. It also illustrates a point that working with them to have a managed version can actually happen.