At the time, things were not as clear cut as they are in hindsight, 80 years later. In 1941, while Hess was flying to Scotland to try to negotiate peace with Britain, Jewish fascists (Lehi) were trying to negotiate an alliance with Nazi Germany. This also sounds delusional in hindsight, and indeed they got ignored by Nazis. But it kind of makes sense if you consider that they were trying to get Germany to fight Britain, which at the time was occupying Palestine (to some extent this also explains why Hitler enjoyed some support in Arab countries).