To answer your question, LR, street gangs could be considered terroristic in nature given certain parameters, as could militia organizations and survivalist camps here in the U.S. It boils down to treatment of the guarantees found in the Preamble to the Constitution: Life, Liberty and the Pursuit of Happiness. When these self-evident rights are infringed upon by means who's result is terror, these groups cease to be gangs, or militias, but domestic terrorism cells.
They all have the right to think what they want, say what they want, and do what they want...as long as they adhere to the laws of the land and take responsibility for their actions. And I have firmly believed, throughout my life, that when you violate or steal away someone else's rights, you forfeit your own.
Street gangs are terroristic if the neighborhoods they 'claim' as they own leads to others being afraid to leave the house, or to sit too close to windows, or to even sit in a room on the perimeter. When shop owners and workers are afraid to go to work, for fear of death, theft, and physical violence. Rarely will a street gang have a political stance. Those that hate hate for a reason, at least in their minds.
These international terrorists hate Americans and the U.S. They may spout rhetoric, but that's just a facade for the deep down hatred they have of us. The KKK really doesn't have a political slant, or even religious; they hate because they can. Black Panthers may also spout political rot, but they too hate because they can. Bigots hate because they can. And you know what? They have a right to hate just as much as they want, as long as that hatred does not infringe upon the rights of others. And though I disagree with their views, I would still fight for their right to express them. One of the downsides of freedom, I guess.
Freedom without bounds is anarchy. Freedom without price is worthless. Freedom without responsibility is just a hollow word.