The whole problem I had is that what SHOULD have happened was completely at variance with what DID actually happen. The Egyptian Army managed to achieve a higher state of situational awareness than was otherwise possible--which meant that they were getting help.
Like Dupuy, I am unsatisfied with the Israeli explanation for the Liberty. I am also enough of a realist to understand that we aren't going to get the honest-to-God truth because Israel understands its place as a Great Power client state--namely, that they are to make themselves look completely foolish in preference to embarrassing their Great Power patron. The United States isn't going to embarrass themselves. Therefore, we are not going to get the truth.
As for why the Liberty was assigned to that mission--do you really think that the government is some monolithic entity with perfectly coherent goals, and that nobody within that government is going to work counter to stated policy?
If you read my previous postings on this thread, you will see I have views similar to yours about why the Liberty was assigned to its mission.