I think some people are just being really irrational here. this topic is about MH3 specifically, not about any other online game. even if you have strong feelings about cheaters in other games, this isn't the topic for it. If you're unable to judge the situation on a case-by-case basis, and control your own feelings accordingly, then that's sad.
MH3 is different from other online games where players compete against each other. This game is different. If you can't even see this simple fact then I am sorry.
Whether someone on your team obtained their materials through grinding or by cheating, has exactly zero relevance to you, and doesn't affect your own online experience. while grinding may be the best part of the game for some folks, for others it may be the worst part. If you really like grinding, do it, just don't force it down someone else's throat and you'll have a happy team.