Turkey does trade with ISIS and nothing happened to them. The thing about covert ops is that you can reject it as the other side doesn't have any concrete evidence to blame you. You involve third parties that doesn't trace back to you. Also, we had supported insurgency in Rakhine long before Hasina came to power. Although, the level was different.
And Burma itself is known for human rights abuse, you just play that card at International level. Not to mention that they have very little strategic importance to big guys (NATO, China, Russia). And China and India are both themselves funding insurgency in their country.