Brad , no you personally don't have to care what Bell used, but fact remains what Bell used on a wide range of PG is not entirely irrelevant, with his moderate velocity .256 and .285 he killed a whopping pile variety of plains game simliar in size and even substantially larger than elk, and Bell makes a very valid point that applies to anyone anywhere, that there is no hard and fast rule in choosing a cartridge, but rather, one should use the rig they have the most confidence in.
So really it is irrelevant as to what Bell used. Please re read your post.