The ones protesting for a regime change.
It will inevitably involve foreign intervention, which tends to work out badly. But I don't accept the alternative, that keeping a suppressive and violent regime is the best case. And I'd rather have the least amount of intervention possible, I don't even intrinsically care about breaking the regime; I want to directly support the protestors as much as possible.
There is another alternative, which a lot of my Irani friends prefer. Which is a regime change without foreign interference.
A puppet installed by US/Israel is a puppet that will only benefit those countries.