I honestly can't imagine what to say to a person who doesn't want child prisons under construction burned down. Like, there's no point of commonality between us, there's no shared overlapping corner between each of our framework of values, no debate one can imagine having.
Say they're inconsistent! Say they're tasteless and need to revisit the indulgent egoism of De Sade, learn how to be properly artistically cruel. If there's nothing reasonable to say all that's left is unreasonable things, so just say the unreasonable thing that's the most fun.