Muslims follow Islamic doctrine.  
Palestinians follow Islamic doctrine.
Islamic doctrine calls for "death to the infidels", and especially, "death to the Jews".
Western nations are nations of "infidels".  But, no Western leader has ever demanded that the Palestinians, or any other Muslim nation or group, renounce the doctrine of "death to the infidels"
No Muslim nation has ever renounced the doctrine.  Very, very few Muslim individuals have renounced it.  The Islamic doctrine of "death to renunciates" may explain that.
And so, Israel is asked to negotiate a peace treaty with a people whose religion calls upon them to kill the Jews, but the Muslim  Palestinians are not asked to renounce the doctrine.
That has been considered to be reasonable, by American Liberal Jews and their fellow Democrats.
Hopefully, it does not look reasonable to Donald Trump,