If we started to, what do you think the response would be? People would be outraged.
Your answer is a non sequitur -- unless you believe the Israelis murdered people on the flotilla.
My analogy is not exact, but it is quite close. True, the Israelis were not attacked while inspecting trucks crossing their border; they were attacked while attempting to inspect a ship approaching a blockaded coast. Aside from that difference, the situations are similar.
If our Customs agents are justified in using force to protect themselves from attackers, the Israelis are justified in using force to protect themselves from attackers.
If we started to, what do you think the response would be? People would be outraged.
Not the DEAD ones!
And any OTHERS who we thinking about invading our country and taking things that are NOT theirs would be a wee bit less likely to try it!