The reason Israel constitutes an 'obstruction to peace' is because the Muslim world does not want it to exist, except as a distraction for its rulers' kleptocratic, thuggish misrule. Of course, if Israel ever ceased to exist, that same Muslim world would still find plenty to war about. Unfortunately, Stephen Hawking has joined the ranks of the mislead.
12 Iraqi troops, militiamen killed in multiple ISIS suicide attacks (AP)
from the article: Israel may not be a pariah, but it's definitely a headache