OK. Let’s assume for the sake of this discussion that hitting the shuttlecock into the net or out of the court deliberately is not acceptable.
If I lob a nice easy serve over the top, or make a soft return to my opponent, is that also unacceptable? If so, exactly how difficult does my serve or return have to be, to count as “reasonable effort”? Would the umpire make a call on this?
Is the argument that certain teams in the competition must always beat their opponents during the round robin, and any other result would indicate that they didn’t try hard enough?
I’m not being contrarian. I think this is enforcing the unenforceable. These athletes are the best in the world, and that’s why they behaved in the way they did. Their objective, as it should be for a successful sportsperson, is to win, and they identified the best strategy for doing that within the rules of the competition. Disqualifying them because people didn’t like the inevitable outcome really is contrary.