בס''ד
Notice that I said, "G-d bless all heroic Jewish freedom-fighters". That is just a generalized statement, not supporting anything specific. That statement is legal even though people can interpret that to mean support for specific individuals or groups.
If someone wishes to express themselves in regard to a specific group like Tag Mechir, it is legal to say, "I do not condemn Tag Mechir". Because no one can legally force you to condemn something.
In regard to this brave young Jew in the picture above, I do not condemn him or Tag Mechir. "Tag Mechir" (Price Tag) is what is written in Hebrew on his shirt.
BTW Tag Mechir is actually carrying out actions quite professionally. They have firebombed mosques, vandalized Arab Nazi property, attacked and damaged Israeli army vehicles and so on. The entire Shabak (Israeli FBI or KGB), the police, and the border patrol are frantically trying to catch them and have not been able to. When an underground organization is able to carry numerous attacks on sensitive targets, that is the definition of a successful and professional operation.
Of course, we are a law-abiding movement both in the U.S. and in Israel. But we will never condemn those Jews who decide to risk their lives and their freedom because they love the Jewish people and the Land of Israel.