So if BLA was to get control of a country like Iran do we continue to support the terrorist group? What makes them any better than the Iran government? All one needs to do is look back into history and see what our support of Afghanistan rebels against the Russians produced.
Supporting the Afghans was the lesser of two evils...the Russians could in no way be allowed to get Afghanistan. And let's not forget, Ahmed Shah Massoud, leader of the Northern Alliance, was one of the rebels we helped...and he helped us later overthrow the Taliban. The Taliban came to power in the late 90's...and not because we helped them in the early 80's, but because we stopped paying attention to Afghanistan later, just like we're not paying attention to Somalia now.
As for the BLA, they may be nutcases, but so what? They're a small ethnic group that will never control all of Iran anyway. The point is to give the mullahs something to worry about at home.