Oh, you can easily unknow it: just as you did to support the American invasions of Iraq and Afghanistan

""And I'm afraid I know too much about the history of the conflict to think of Israel as just a tiny, little island surrounded by a sea of ravening wolves and so on. I mean, I know quite a lot about how that state was founded, and the amount of violence and dispossession that involved. And I'm a prisoner of that knowledge. I can't un-know it."" (thanks Redoune)