Notes that they take are for themselves. So they may write down things such as "Patient mentions ____, possibly delusional". That's an odd example but the first I could think of off the top of my head. To see that you might be offended for no reason at all. They have to write down little things as a reminder to themselves to follow up or check on things as they are running through their head. This could cause unnecessary harm to the client. Which is why those notes are not for patient viewing.
They're not meant to bash the client. But to make sure the therapist is keeping a running reminder of flags that go off in their head.