Having the same company own both the main engine (InnoDB) and the harness (MySQL) has been tremendously valuable.
I may be a bit ignorant, but what have they done with MySQL?
Perhaps "hate" is the wrong word, and it should be more "dislike", since Oracle are essentially the complete opposite of what Monty wants to encourage (e.g. Hacker Business Model, Open Source). My memory's a bit hazy, but from what I gathered, Oracle tried to stop MySQL in its early days by acquiring the INNODB Engine around 2005. After that, once Oracle acquired Sun and thus MySQL, Monty and many of the other original developers saw Oracle as being against the spirit of the original intention of MySQL, shifting away from the principles they wanted to encourage, particularly open source philosophies, and they wanted to make sure a version of MySQL would always stay free. From what I recall, he believed that Oracle were no longer fixing known bugs because they didn't know how, and they were also moving from "open source" to "open core", where new features were closed source.
I do appreciate Monty's efforts, but really, can we kiss and make up? And if oracle wants to monetize MySql, so what? The rest of us get a better database.
Also it should be noted that the InnoDB storage engine was developed outside of MySQL AB. InnoDB is a helluva lot better than MyISAM for most applications because of performance and support for transactions, consistency, etc. Without it I don't think that MySQL would be a good candidate for many applications, particularly given that Postgres has improved a lot. I.e. I'm not sure Monty should really get credit for everything about MySQL/MariaDB.
That said, I wouldn't put it beneath them...
Not that the takeover is feasible, as the other answers point out.