The illegal Mexicans are looking for a job. They're not condoning the genocide of all Americans, and streaming across the border to conduct terrorist attacks.

You really can't draw that comparison here, and it's very difficult for westerners to really comprehend the worldview of nations in the middle east. Ethnicity and nationality holds far more importance than in the west. Without an armed response the Israelis themselves would likely be subjected to a worse situation than their counterparts. The nation is obligated to place its citizens' interests first, regardless of who's right or wrong, or 'who started it'.

It seems like overkill until you understand how impossible the security situation is. Far more suffering would occur if the border weren't held so unwaveringly. The region is just a shithole of mutual wrongs, and there isn't really the luxury of a diplomatic, or even a humanitarian resolution. It's an awful situation, but you can really only look at it through the lens of the various stakeholders rationally putting their own interests first.