Sharpton’s certainly said some very antisemitic things and I believe he is responsible for a Race riot that may have cost one Jewish person their life. However, I can see the National Jewish Democratic Council being more concerned over a candidate who would speak to the NAZI party. After all, the the NAZI’s murdered murdered over six million jews. Which I believe was about 1/3 of the Jewish population at that time. So, I think its fair to draw a distinction between a bigoted, hatefull man and a party which wants to kill all Jews.
The Nazi party in question has not actually killed anyone or incited fatal hate crimes, no matter how reprehensible its ideology might be.
Al Sharpton has been at least indirectly involved in two incidents in which people were killed. The race riot to which you refer was a reenactment of the Night of the Broken Glass, with Sharpton’s followers yelling “Kill the Jews.” The other was the fatal arson of Freddy’s Fashion Mart.