> it had been calling itself a 'database' product while specifically defaulting to doing the least possible to make sure your data actually hits the disk
Being a database doesn't mean you have to persist on disk. There is nothing wrong with in-memory databases. If you thought they were giving you persistence guarantees, then yeah, you would have a gripe.
In memory databases are explicitly marketed as "in-memory database". Not simply as "database" because that delivers some expectations to people. And those expectations are generally not verified with the dictionary definition of database.
Being a database doesn't mean you have to persist on disk. There is nothing wrong with in-memory databases. If you thought they were giving you persistence guarantees, then yeah, you would have a gripe.