I agree with you too Cullen. It isn’t the butterflies fault.
My way of trying to avoid a plague of white butterflies on my brassica is to grown brassica plants mostly outside of the lifecycle of the whites (ie) April to october. I do start the plants early in late feb-march and have to be prepared to take caterpillars off by hand for a few weeks. I do dread to Large White butterfly though because the larvae can completely skeletonise a cabbage due to the concentration of eggs laid. Unlike the small cabbage white which lays its eggs individually and over a larger area, rather than in concentrated batches. The damage from the smaller white is seems more superficial.
Of course you are absolutely right Cullen. The Large and Small whites are just doing what comes naturally and taking advantage of a human food resource, that just happens to be of the right plant family for the larvae to feed on. If we humans did not like eating plants of the cabbage family these Butterflies would in some areas be quite rare. I often think about how these species survived when my country the UK was heavily forested many thousands of years ago. Yes, there are many plants of this family that grow wild in the UK and the larvae will feed on, but not in such vast numbers as the domesticated varieties of cabbage.