RE: do we need semi-auto rifles
If you wanted to pursue it even farther you could ask the question, "Do wereally need to hunt big game with rifles period"? I mean there is always a bow.... Then we could continue and say do we really need to hunt big game at all?
It isn't a matter of need as I see it. I don't own a high power semi anymore but maybe someday I will. This type of thinking starts us down a very slippery slope. Keep chipping away at the 2nd Amendment and eventually you won't be able to own that bolt action you love (of course being from Canada that wouldn't apply).
It doesn't matter what other people use tohunt their game as long as it is done legally and ethically I wouldn't be critical.