I remember when America would let in many foreigners during the civil rights movement in the 1960's. They would be part of the many marches in the south that fought to end Jim Crow laws against African Americans. I guess Israel is to paranoid to allow itself look bad to the world. By not allowing the protesters in they just make themselves look like a country that is not democratic but more like Syria next door.
Woman moderately wounded by firebomb thrown at her car in north J'lem (Haaretz)
from the article: Israel should greet pro-Palestinian activists with flowers