Exactly. This controversy was both discovered and promoted by Monty, who has much to gain by the rejection of Oracle's brand of MySQL and the promotion of MariaDB. Having said that, I agree that this is a dick move by Oracle. It reminds me of when RedHat started shipping their kernel as one big source tarball, without patches, which undoubtedly pissed off both Oracle and the CentOS folks. Maybe they're taking a page from the RedHat playbook.
Forgive my ignorance, but doesn't this harm MySQL forks as well? Since the test cases are unavailable from now on, say for example they wanted to reimplement a certain feature, isn't it much harder for them to validate that their implementation works correctly?