This is my view as well. You’ve already paid for the books. You’ve already supported him. Putting them in the bin doesn’t unsupport him. Although if it’s only going to bring you sadness seeing them on your bookshelf, or you don’t think you’ll be able to read them again knowing what sort of person he is, maybe a donation to an op shop might be an option.

I dunno. Donating the books is the option I’d choose, but it depends on your own beliefs, values, and moral compass. Personally, I don’t see it as supporting his work, because no money goes from the resale back to him or his agents in any form. And I’m pro preservation, and see destroying works created by awful people as throwing the baby out with the bathwater. But there’s also the angle that you could be introducing and enabling the spread of his works