Why do you think critical thinking is relevant for the 21st Century Students ?

I am not sure it is relevant for most students.

It is their job to listen to their teachers and to regurgitate what they have been told at appropriate times. Critical thinking will just lead them to find problems with what they are being taught and that will lose them marks and reduce their grades.

It is still important 

Yes.  Critical thinking will only be effective if we adopt socialism.