Noone likes to have their kindness thrown back in their face so the reponse from ordinary Israelis might be seen as justified. However, attacking the sudanese immigrants is racism, plain and simple. The real protest should be against the government for not attempting to deal with the forseeable problems of this type of economic migrant and the police for ineffective policing.
U.S. to defend Syrian rebels with airpower, including from Assad (Reuters)
from the article: Demonstrators attack African migrants in south Tel Aviv