It happens because of the basic rules of those matrix operators.
All of your matrices are 3x3. Both of those binary operations (* and /) between 3x3 matrices result in another 3x3 matrix.
My guess is you have invented in your mind a new rule for the / operator, wherein it becomes a matrix concatenation operator, or something like that. Sorry, but operators have explicit definitions in MATLAB. They follow their defined behaviors, as I would hope they should.