It needs oil. Oil will break down the adhesive and shouldn't be hard to clean off of a sealed/finished surface. I've used anything from a few drops of cooking oil to peanut butter (doesn't run!) and let it sit. Depending on the adhesive it could take minutes or hours, but typically makes removal much easier.
I feel for this one. This is such a stupid common thing. I also hate the thing where packaging was made more difficult to discourage returns but that thankfully has at least reduced from its height.