Jeff, it's not an "absolute". You'll notice I said "generally" a buck likes to get a tree in between his rack, which is true. The bigger the tree the odds are better that it's a bigger buck rubbing it, that's a fact. He does this because he likes to push against it to get some resistancefrom it. Other's will sometimes just rake it to mark an area/rub line.
Small bucks, spikes,4pts, little 6pts ect, don't usually fool with a bigger trees.I think that's all that's being said here.