More important you should ask how his remarks were covered by the American TV networks. NBC's Andrea Mitchell said Biden was just hitting back at the way Israel "punched him in the solar plexus" with its announcement. The Israeli move was seen as insult timed for maximum effect. You Israelis seem to have a knack for that because you seem to be completely out of touch with public opinion in this matter.
Police disperse hundreds in brawl in Kafr Manda, northern Israel (Haaretz)
from the article: How did U.S. groups react to Biden's condemnation of Israel?