Is he really THAT off base? Honest question. Like I said, I'm green with this stuff.
His point of view is one that I disagree with totally. That said, there are many that say to go even lighter. You will get many differing views among bowhunters. It may take awhile to figure out what you think will work best.
There has only been one person who has extensively studied big game kills and the mechanics of what works best- especially when the hit is in a less than ideal spot (which everyone is prone to - everyone!). I highly recommend reading his studies, which can be found here. Be prepared for a lot of reading. He's been studying and writing about this for many years. At least you'll have the perspective of a guy I consider one of, if not the only, true expert on arrow dynamics when hitting flesh and bone.
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=forum;f=24