RE: sniper rifle for hunting?
The definition of a Marine Scout/Sniper: "A Marine highly skilled in field craft and marksmanship who delievers long range precision fire at selected targets from concealed positions in support of combat operations."
Nowhere in that definition does it state anything about which weapon system they use to conduct their job.
Snipers use the M82A1 because they know how to employ a scoped weapon better than most, but, snipers aren't the only ones who use it. LAR, for instance... 10th Marines (Arty) use it, but it is not a "sniper rifle."
The reason that you need a precision weapon such as the M40A3 which is capable of holding that minute of angle is due to the nature of the beast. When employing the M82, it is typically, as you quoted, an anti-material weapon. When you are shooting a light skinned vehicle, precision just sometimes doesn't matter. That, is also why it is not a "sniper rifle."