be for a good cause
To have a beneficial, often charitable, aim or effect. Oh, the money's going to charity? Sure, I'm willing to donate a few bucks, since it's for a good cause.
be (all) for/in a good ˈcause worth doing, because it is helping other people: Most motorists seem to accept that the speed cameras are all in a good cause (= they help to keep people safe on the roads by stopping people driving too fast).