As a teacher it is your duty to differentiate for your pupils . It is hardly a huge task to use a textbook or have the odd worksheet ready.
If the removal is followed by a sanction it should not be seen as a reward. I usually just have to say to someone playing up in my class " if that continues you will be removed " and they back down. If I had to have the same pupil removed from my class lesson after lesson it would be clear that a more long term solution was needed. Whether that would be a permanent removal from my lesson, a longer removal from all lessons, an exclusion or me reflecting on my own behaviour management and teaching would depend on the case.
I think pupils are reluctant to be removed from class because school policy is that if a students removed from class they have a school detention and they have to retake the lesson after school, making sure all of their work is up to date.
I currently have a Key stage 4 class that are quite difficult and that I know many other teachers are struggling with, especially female teachers. As a professional I have accepted that I cannot place all the responsibility at the door of he children and I am currently working on my own behaviour management and and planning. I have been observing colleagues and we have also set up a group of teachers who are working as a group with senior teachers to look at how we teach this difficult group of students. The emphasis is not on blaming the individual teachers but asking as a body of staff what can we do differently .
There may be an impression given that pupils are currently always being removed, in most schools that is just not the case. I teach two of the most difficult classes in the school, one of them is new to me so I am having to lay down expectations, I have not not had to remove one pupil all half term. I have had to in advance arrange for a few pupils to work elsewhere and I have had to set detentions and phone parents.
I don't think that students should remain in school, if after the school has done all that it can, the student refuses to behave as expected and continues to disrupt. As I said earlier, I have recommended that students are permanently excluded and some students have then had to move to a behaviour unit or a different school.
I agree with you, that the harder tests are a red herring.
From reading your posts Ronaldo it is clear that you have had a very painful state school experience in which you were key down by ineffective leadership. That is a real shame, no teacher should feel powerless and ignored and I am not surprised that you feel bitter about that.