I don't like him because in the end he is always liberal first and come the elections would give again the Jewish seal to the next candidate. And he is not a stupid person so he knew what Obama was al about when it comes to Israel from the get go. Also the Iran deal is far worse and tangible then the UN declaration and it didn't stop him from endorsing the democrats and Clinton who supported it.
Finally I think he breeds antisemitism because I can think of nationalistic minded Americans who hear him praising the destructive internal policy of Obamaism which could bring an end for America as we know it and there he says he supports that, it's only the destruction of Israel he tries to prevent, America can go down the drain.