"Lately I have noticed several players getting more and more upset over having other players from rival groups plunder their hard earned coupons."

The coupons were never earned (past tense), they will be rewarded for a successful convoy mission (future tense).

"no, you are supposed to fight for a chance to get it, not just mindless 1 mil attacks 120k"

Who said? Oasis said?

If plundering was meant to be a close fight, it would have been designed that way.

This game is based on ninja that brutally murder each other.

Released Madara vs the Allied army to name one example.