"A nation can survive its fools, and even the ambitious. But it cannot survive treason from within. An enemy at the gates is less formidable, for he is known and carries his banner openly. But the traitor moves amongst those within the gate freely, his sly whispers rustling through all the alleys, heard in the very halls of government itself. For the traitor appears not a traitor; he speaks in accents familiar to his victims, and he wears their face and their arguments, he appeals to the baseness that lies deep in the hearts of all men. He rots the soul of a nation, he works secretly and unknown in the night to undermine the pillars of the city, he infects the body politic so that it can no longer resist. A murder is less to fear"
Cicero Marcus Tullius
He has the right to say anything he wants.
It is also undignified and unprofessional for a sitting President to express opinions, even when asked, regarding what is essentially a private business matter. In this case, by expressing disapproval of the current name, he implies that he (and his office) would endorse measures to change the name, including but not limited to boycotts, etc. Implication of endorsement of action from the President of the United States is no small matter. No, it would have been better to politely decline to answer.
After he leaves office? Whatever he wants to say or do is fine.
If, when defending your support for Donald Trump, and your response is,
"But but but... HILLARY!!!", then you lost the argument before you even began.
- Colonel Paul YinglingNobody who wins a war indulges in a bifurcated definition of victory. War is a political act; victory and defeat have meaning only in political terms. A country incapable of achieving its political objectives at an acceptable cost is losing the war, regardless of battlefield events.
Bifurcating victory (e.g. winning militarily, losing politically) is a useful salve for defeated armies. The "stab in the back" narrative helped take the sting out of failure for German generals after WWI and their American counterparts after Vietnam.
All the same, it's nonsense. To paraphrase Vince Lombardi, show me a political loser, and I'll show you a loser.