If the separation of art and ethics is a problem, how about a pragmatic compromise?
If you like a work, but think its creator is a dubious ratbag, your reaction depends on whether your liking of that work will benefit the ratbag.
If the ratbag or his/her estate will benefit from your appreciation, then, fine, shun the work. However, if the ratbag's dead (Carravaggio, Byron, Mozart, Wagner - or even Lewis Carroll, Grahame Greene, Ben Nicholson, John Lennon....), enjoy. Ars longa, vita brevis.
Because, unfortunately, there seems to be a correlation between being a dubious ratbag and being the creator of great art. If we're to be po-faced we might as well start holding exhibitions of "degenerate art"....Oops, forgot - that's already been done.