If you've got time and patience, you can kinda counter roll the edges of the clamp to ensure that bit doesn't apply pressure to the rubber.
Pliers or vice grips would work, but ideally straightening the clamp out them peening it over a dolly would be the smoother/neater way.
Conversely, a strip cut from an innertube and used between the clamp and boot as an insulator would also work well.
Or, just don't tighten the clamp so much
