I think the analogy doesn't fit since it's about two different species. Or three, if you could monstergirls as distinct from small bugs.
It'd be more akin to a non-terran race (that kills humans as if an invasive species) unilaterally paying for humans to promote their culling tools. Species lines are crossed, unlike monstergirl's analogy. Unlike human self-defense weapon advertisements.
Further arguments can be made about non-sapient bugs vs monstergirls. We don't like seeing mice getting killed, but they're closer to humans evolutionarily than bugs. And we humans have no problems with killing mice as pest control... though some humans are squeamish about it. And prefer any killing be done ethically (poison, etc).
So closer analogy would be comparing it to aliens asking humans if they're OK advertising for mousetraps, as fellow "mammalia".