A few days ago I caught a Black Swallowtail (Papilo polyxenes) in the act of laying eggs on my parsley in the herb garden.
People love butterflies, but I think they often forget about the caterpillars they start out as. When a person sees a caterpillar eating a garden plant, their first reaction is to kill it. Now, I don't like it when caterpillars completely decimate my garden any more than the next gardener, but I do try to hold off on the bug-killing unless they're really causing serious damage. I plant a lot of parsley and never come close to eating it all myself, so I don't mind sharing.
I'm reminded of an article I read a little while ago about how Monarch butterflies (Danaus plexippus) are having trouble finding enough milkweed, because milkweeds are usually killed by farmers and gardeners, being a weed and all. The article recommended to plant milkweed to give the caterpillars something to eat. I think milkweed is pretty cool looking, especially Antelope Horn, but I understand that it's the kind of plant most people would not consider pretty. It's certainly no Texas Bluebonnet or Indian Blanket.
People like butterflies, but butterflies come from caterpillars, and caterpillars need something to eat. That means you need to have their host plants (and they're usually very picky about host plants), and then you need to have the caterpillars eat the plants. If a gardener doesn't like the host plant, they're probably not going to have it in their garden to begin with, and if they do like the host plant, they probably won't like letting a caterpillar eat it.
But that's what you have to do if you want butterflies.