One of the Merriam Webster definitions of bigot that is relevant here is:
one who regards or treats the members of a group (such as a racial or ethnic group) with hatred and intolerance
Marley and you regard White people with intolerance and that makes you bigots. Any time you judge a person based on skin-color and not on what they say or do, you are betraying prejudice.
I hope that clears up the definitions. Once you acknowledge that Marley is propounding a philosophy of racism against White people, the next question is why you even try to defend it. I believe it is unethical and immoral to judge someone guilty or innocent, inferior or superior, on the basis of their race. It is the essence of Justice to hold each individual accountable for their own sins and not the wrongs committed by others.