Get a grip. Police use undercover agents to "spy" on criminals of all walks of life all over the world - because they are Criminals. This story deals with the fact that the criminals in instance happen to be Arab and therefore agents need certain expertise (language, culture, etc.) Regarding security threats - do you think the FBI doesn't infiltrate (or try to) potentially threatening organizations? Also - what may be "vile" about the palestinian arabs, is that while most of us would love peace (or even non-violent coexistence) most arab leadership cannot and will not relinquish its claims to destroy us entirely. So if it takes a wall, or an electric fence or a squad of soldiers to keep people who want to kill me over on their own (or potentially own) land, so be it.
Report: Car bomb kills 10 in Syrian port city (AP)
from the article: Secret police unit monitoring Israeli citizens