“It would be crazy not to do another experiment to check this result,” Rouven Essig, a theoretical physicist at Stony Brook University told Nature News. “Nature has surprised us before!”Apart from Feng et al and you I don't see anyone seeing that reason.Sorry, mixed protons and neutrons. Make its coupling to neutrons stronger then.It does not. The theorists are exploring "what if". They hope to be right, but that is a different statement.
Rouven Essiq is at least 1 other physicist other than Feng et al. Other news articles quote other particle physicists who think it is worth researching and experimenting.
Lubos Motl is one string theorists who regards string theory as truth. Other string theorists from Michio Kaku to Brian Greene to Ed Witten to Stephen Hawking promote string theory, so its definitely past a what-if for them.