Horrific injustices and humanitarian catastrophes are ignored all the time; in fact, that is the default response.
So the questions activists should be asking are: What is the incentive to take a stand on the Rohingya issue? What geopolitical and economic benefits are there to defending the Rohingya?
If you can frame your advocacy in these terms, you might make progress; if you cannot, then do not expect moral pleas to resonate with policymakers