The claim that you can't describe consciousness in principle is widely accepted by participants on all sides of the debate. Can you tell me what experiencing red is like to you such that someone who is red/green color blind will know what its like? Most people think not. Rather, phenomenal consciousness is something you must experience yourself. It just isn't something that one can learn descriptively. This is a premise of the hard problem and also the Mary's room thought experiment. People who reject the premise usually just reject phenomenal consciousness completely.