To the OP's question"Isn't a heavier rifle better for a typical stand hunter"
OP,if you determine that is what is better for you,I'd say you are right..for you.
I figure as long as the hunter can make a clean kill,they might have just what they want,or,they might be hunting with the rifle they have,or it might be Dad's old rifle,or grandpa's.
I like light rifles.I spend more time carrying than shooting.I shoot better fresh than tired.A light rifle is more likely to be in my hands than leaning against a tree.
But,other things come into play,last antelope season I used a military trim 1903A4 copy.Not so light.Worked fine.I used it because I built it and I just wanted to.
On a stand,for a deer,If I had (I don't) a mini mauser in 6.5 Grendel with a 20 in fwt barrel in a foam core Kevlar stock with a light fixed 4x scope,say all up < 6 lbs,I'd think 250 yd deer would be no problem.
If my bro chose to carry an AR-10T,just because he is a one rifle guy,no problem.