The only thing Oracle is doing wrong is thinking that no one could be bold enough to try and sell the same product twice.
It's a gutsy move. It really is. Sell MySQL to Sun. Claim Sun's purchaser is doing __________ (fill in the blank with whatever evil nasty thing you like) with it. But that's ok, MariaDB will save you from that. Distributions flood to it to get away from the nasty big evil corporation, and suddenly Monty has legally taken back control of what he sold for a cool billion dollars.
The best part about it, is if Oracle says anything about it, then it just looks like they are trying to trash talk the little guy who is just trying to do the right thing for
the community.
And before you think of flaming the idea, remember, Monty is very much the businessman. He almost invented using the GPL as a weapon. He stopped releasing any connector or client licensed as LGPL so he could claim that even using MySQL as a back-end for something else required the entire front-end to be GPLed too - either that or pay him for a commercial license.
The next company to buy something from Monty better get an iron clad agreement never to fork it.