Ours don't. I would look and see if there is something nasty hidden under the Hosta leaves.

The hostas themselves don't attract horseflies, but something else apparently is. The hostas just conceal the problem. Did something do it's business in your hosta patch, a cat, dog, dead bird, whatever else is walking around? That's what horseflies like. They play an important role in decomposing dead organic matter. If you get down and look around under the leaves, you shouldn't take long to find the problem.

There you are, something nice to do tomorrow...