Hey, I didn´t claim that they are prohibited. I do of course know that you can use them, in fact you even should because otherwise it will sound boring.
These notes are just in certain musical situations limited applicable. And of course, you can play every note over every chord.

But when I imorovise I mostly do not end with one of these notes because the danger of a weird sound would be probable. I just use them just as the chromatic notes between the other notes. That´s where my improvisation skills ends, I guess I use too little variety in my solos, in theory.

So the whole avoid notes thing is from a theory book written by Frank haunschild, who is known as a great jazz guitarist, and I don´t see why he should write something scenseless in it.