Tough topic for these insects that end up being colourful butterflies. I avoid killing our crawling or flying friends in the yard that all have their place on our tiny earth. Destroying one just ends up putting all the others into an awkward stance.
Take aphids, for example. When I find aphids eating away at the spring sprouts on my citrus trees that ants "milk" and protect - I do end up breaking the rules. Nevertheless those ants take care of a great deal of house cleaning on the grounds so clearly not negligible partners.
All in all, I don't know how this larva will end up one day but it looks poetic on the leaf it's eating away.