CBT isn't as simple as "you can control your thoughts". It's a carefully structured plan of therapy to give a person the skills and techniques they need to control thoughts.
By saying, and repeating "you can control you're thoughts" without giving any of the detail of CBT you're merely telling people with depression to just think themselves happy.
Also, people with OCD will find it harder to control their thoughts, and people with psychosis may find it impossible without medication.
> Are you saying that it's impossible to control your thoughts?
Given that thought generation is not a process that you (the person) actively control, that seems rather obvious. "Thoughts" would refer to all of them, and many thoughts are intrusive or otherwise do not originate from "you" (i.e., insights, creativity related thoughts, odd memories, associations, etc., etc.).
You can have thoughts about thoughts, and you have a greater control over those because you /are/ more or less actively generating those, but that's not true for most thoughts you have.
Even then, the control space is very limited (not truly deserving of the term control) and only available to people who practice a lot of introspection. CBT is a tool in making one's way there. It's not something that the average person can get up and do. "You can control your thoughts" is therefore not the most useful statement, we're not discussing what's possible in theory, we're trying to help a specific person.
I do not believe in freedom of the will. Schopenhauer's words: "Man can do what he wants, but he cannot will what he wills" accompany me in all situations throughout my life.
Only if you decide it is such. I've suffered major depression for many years, now, and the advice given is good and will help some people. It's much better than the usual trite "just think happier". It might not help those of us who are deep down the rabbit hole, but it at least, to me, seems not to hurt.
For instance:
> The key thing is to realise that YOU control your thoughts. We're creatures of habits. YOU choose what to think whether you realise it or not.
Rather, you choose what to think of those thoughts you have.