I agree with everything you said 100%. True, there are far too many individuals who don't take the moral consideration to learn the dynamics of what they choose to hunt with. And, you're right, the 300 WM is one of the finest long range hunting rifles available to the hunting public. I own one myself and have quickly learned just how powerful that caliber is.
However, the OP's question was: is the .300 WM too much
for deer... and he asked for the best factory loads in 180 gr. Of course, the 180 gr 300 WM will kill the deer...dead as a doornail and quite spectacular I might add. A 20 megaton thermonuclear warhead would certainly kill a deer as well.
What I was stating (and I used JBM Ballistics for a reference) was that, if he wanted to eat
the deer, he should consider a lighter load that would still certainly kill the deer. With a little research, he could find a load (factory even... maybe a lesser grain) of less energy at that distance, kill the deer with certainty, yet not blow a good portion of that precious meat across the countryside to feed the dingos.