In my opinion, no, you are not wrong. Furthermore, and the arguments that since you knew about the policy to begin with you don't have a leg to stand on, and that since the policy applies equally to all students it cannot be claimed to be unfair, are simply invalid and are missing a key point (which I'll address at the end) about where the unfairness comes from. Let's examine these two superficially compelling arguments more closely.
We can further illustrate the falseness of the "applies equally" argument by taking the same argument to an absurd extreme. What if the grading policy said that 15% of the grade would be given for the ability to recite the first 10000 digits of pi? (Let's assume that memorizing those digits was not one of the goals of the class, which seems like a fair assumption.) And let's assume that all the students except the OP managed to perform this feat and got the 15%, and he alone failed. Well, the policy was the same for everyone, so it is "maybe unreasonable" but "certainly not unfair" - right? Clearly that's nonsense, because the point is that (as I explained above) such a policy is grading based on completely irrelevant information, and hence discriminates against the OP compared to all other students everywhere who are evaluated on their knowledge of the same material as covered by the course.