Let's be honest here, and I say this as an Indian. The real reason we got independence is because Britain was exhausted after ww2 and couldn't retain her Empire anymore. It's no mere coincidence that all the other British colonies gained independence around the same time. All Gandhi really did was organize India a bit, and Britsin was happy for it, since he pacified most of the resistance.

Not wanting to get involved in a distant war is a reasonable position tho, especially since Britain promised freedom for Indian support in ww1. If you really want a case of Gandhi's idealistic dumbassery, there's the time he said the Jews should all surrender themselves or run of a cliff to soften the nazi heart.