You are misunderstanding the intent. If Hunter is not present it makes it far easier for the Howard Baker protoge to appear conservative. Otherwise, I see no reason, other than pure hatred for one to be so excited about a candidates departure, who by their own admission has only 1% support.
There is a reason and it is based on mathematics. Surely you are smart enough to figure out why it is desirable to not have an unlimited number of candidates on a debate stage.