There isn't an adult moth or butterfly on the planet that can do either you or your property the slightest harm. Some of their caterpillars can be a pain. Processionary moth caterpillars in plague years can seriously damage forest trees. Large white butterfly caterpillars are a bloody nuisance on my brassicas. I've grown calabrese before now that's been "more meat than veg". But when we grow large areas of monoculture crops or plantations we are just Inviting trouble. With plenty of biodiversity nothing becomes any more than a bit of pain for a short time. Nature hardly ever produces monocultures and rarely has plague years of anything if left to itself. We should learn from that. I love butterflies and moths, in fact I've just bought some lovely field guides and I'm educating myself. That moth you're calling bad took three billion years to evolve into what it is. Until we came along there was nothing bad about it. I wonder what it thinks of you, coming along in your size tens ready to stamp on it.

      
"I would not enter in my list of friends,
Who needlessly sets foot upon a worm.
An inadvertent step may crush the snail
That crawls at evening in the public path,
But he has the humanity, forewarned,
Will tread aside, and let the reptile live." [William Cowper]