The current regime in Iran can never, under any circumstances, be trusted. That's been obvious for the nearly five decades they have been in power.
I agree, there's nothing to be gained from trying to create liberty where the people obviously do not desire it, and, honestly, are not even intelligent enough or moral enough to want it or make it work.
There's a substantial segment of the population in Iran that does want it. The question is, do they want it badly enough, and are the willing and able to fight hard enough, that reasonable assistance can help them attain it.