I believe we need to define challenge or at least discuss it here. A lot of us find hunting IS a challenge, and the weapon type determines some of the challenge no matter what weapon is chosen. Rifle hunting (even) has it's challenges, to each their own.

I do not believe there is anything wrong with considering hunting a challenge.

As far as taking "unethical and irresponsible shots," that is always a hunters choice no matter what reasons he has for hunting.

As for me, I both hunt for the excitement and the meat, as KRal says, and for the challenge.