1. We are a country of laws, not of autocratic presidents. Therefore it is the task of the judiciary, and only the judiciary to decide this matter. I have full confidence in the judiciary to do so and to come to the right conclusion.
2. And I have a pretty clear idea of what the right conclusion is: what the Turkish president demands is ridiculous. In fact, the fact that we have a law that allows him to demand this is ridiculous. We are therefore getting rid of the law.
Not allowing the prosecution to go ahead would have sent the message that autocratic decisions by the executive in judicial matters is the correct way to proceed, regardless of which way the decision goes. It also wouldn't have sent as clear a message as to the ridiculousness of the request as getting rid of the law.
Again, not usually a fan, but this is damn good.
As many others have pointed out, the relevant law  explicitly requires an autocratic decision by the executive before prosecution can start.
So in this situation, you are a country of laws being mediated by an autocratic president. It is the task of an autocratic president, and possibly the judiciary, to decide this matter.
Exactly. This is why the law is an anachronism and needs to be repealed. And why using it to get the "right" outcome would be inconsistent with the principle of rule of law that says it needs to be gotten rid of.