How about we think about it this way, three competitors win gold but do not sing the anthem. Mark Cavendish, Mo Farah, and Tiffany Porter.
If Cavendish decides not to sing the press would think nothing of it. He was probably savouring the moment, or welling up or some such thing.
If Farah decides not to sing it would raise a few eyebrows but he sounds like a Londoner and is raising a family here so the press would get over it.
If Tiffany Porter decides not to sing. The press will kick up a sh!tstorm claiming that she didn’t sing because she considers herself an American and takes no pride from competing in a GB vest.
This is what he means by targeting certain athletes. The performance director is not at fault for trying to stay one step ahead of the British press.