In a free country, citizens are permitted to speak publicly on any topic of their choice. If they should choose to defend the political ideals of national enemies, this is protected by their freedom of speech. Although these statements may be unpopular, they are legally permissible in any free country.
In our country, the ability to speak freely is defended by the first amendment. Although it is unpopular to defend enemies of a nation, it is a person's political right. As long as the statement does not violate any other law, there is no reason that someone should not be able to express their political belief.
The classic saying is that freedom is speech means defending the rights of those who say things that you hate. A nation could be at war, and everyone could be for the war, but people should protect those who wish to speak out in favor of the enemy - they probably won't be in a position to do so for long, anyway.
By protecting a nation's enemies through written or spoken word, people are exercising their right to free speech. Such an action is only treason if those individuals take direct action to aid the enemy or hurt their own nation. With that in mind, free speech is protected in America, and people can say or write whatever they want.
Due to the laws allowing free speech and thus defense of the enemy, unless acted upon, defense of the enemy is simply voicing opinion and therefore not treason. Not saying that I agree with complete, free speech. I actually have the opposing point of view. However, in a purely practical and current sense, defending the enemy is not treason due to the laws that make it so. Is it ugly? Yes. Does it indicate a problem? Yes. It's regrettable that so much defense of the enemy is possible.
Defending a nation's enemies is treason. This is what I always thought but could be wrong on the issue. However, anytime you aide or defend a nation's enemy and are caught you are usually charged with treason. It is wrong to not come forth and report anything of the sort.