This is part of what's wrong with how the media is dealing with Trump. He did not do what they said here. What he did was express his personal opinion that something should happen to flag burners. Not that something will happen. Not that the law is going to change. Not that he's going to ignore the law and enforce his opinion. Not that he's going to propose a constitutional amendment to ban flag burning. None of that. Just his own personal opinion that something ought to happen to them.
They keep reacting to everything he says as if it was an official pronouncement of policy and enforced with Presidential power. They should just accept his tweets for what they are, the personal opinions of one person, who happens to be the next President. As President, if he actually wants to do anything, it won't be through a tweet. They should react to that.
Between Hillary and Trump, only one of them pushed Legislation in the Senate to outlaw Flag Burning.
Hint: Trump has never served as a United States Senator.