Here the control refers to whether the outside world happens the way you like it to happen or not. Things happen for reasons and not because you want them to happen.
For example, if one wants to light a fire, he has to provide reasons to light the fire and if he wants to put out the fire, he has to take the reasons away. This is providing reasons for something to happen. This is not the control. If he had control over it there should not be a fire even after providing the reasons for the fire to happen.
This argument was brought to Lord Buddha in front of all the kings by a Brahma (I think the name was Baka). He argued that there is control and that he can do what he wants because he was a high powered person.
Lord Buddha asked him if the king wants to kill him (This Brahma) Can he kill him?
The Brahma did not have an answer because if he said yes, that means he loses the argument in front of the kings and the crowd. If he said no, then the king can order for that to be done. So he lost the argument.
The point is we can think about lustful thoughts all day long but can we stop thinking about them whenever we want? We should be able to do that if we have control. That is the control. Unless you go to Dyana, you cannot stop getting lustful and hateful thoughts 100%. All one can do is provide reasons or eliminate reasons.
Like Lal mentioned, if you understand Patichcha Samuppadaya, you get a feeling of how this works. It is all connected and if there is a Raga (lustful) Vinnana, then it will result in Raaga Naama Rupa.
Try to think of the person who you like most for 2 minutes if you can. But make sure you don’t think about a RED BABOON. See if you can only think about that person and not even focus on any noise you hear.
What is meant here as control is having total control. Controlling diseases by medication is providing reasons to change the result. This is not the control. Control is not getting any diseases because no one wants diseases. It is about what you really want and what happens. It differs hence why people suffer. If everything was in control, then there won’t be any suffering. But then if one was in control of everything, the others would suffer because they have no control. This is a feature of the world that one needs to realise in order to walk the path of Nivana (cooling down).