I remember this incident well, also that same year the north Koreans commandeered the USS Pueblo, also a surveillance ship gathering intelligence. It hard to say what the reasons were for either incident, but of course people can read into it what they want. By the way, one of the biggest spy scandals in CIA history, involved a mole for Israel. Aldrich Ames. It's almost as if they don't trust us or something. They say, keep your friends close, and your enemies even closer...
It's also useful to contrast the behavior of the US Congress after each of those incidents.
With the Pueblo, congress left no stone unturned.
With the Liberty, congress turned a blind eye.
"That on June 8, 1967, after eight hours of aerial surveillance, Israel launched a two-hour air and naval attack against USS Liberty, the world's most sophisticated intelligence ship, inflicting 34 dead and 173 wounded American servicemen (a casualty rate of seventy percent, in a crew of 294);
"2. That the Israeli air attack lasted approximately 25 minutes, during which time unmarked Israeli aircraft dropped napalm canisters on USS Liberty's bridge, and fired 30mm cannons and rockets into our ship, causing 821 holes, more than 100 of which were rocket-size; survivors estimate 30 or more sorties were flown over the ship by a minimum of 12 attacking Israeli planes which were jamming all five American emergency radio channels;
"3. That the torpedo boat attack involved not only the firing of torpedoes, but the machine-gunning of Liberty's firefighters and stretcher-bearers as they struggled to save their ship and crew; the Israeli torpedo boats later returned to machine-gun at close range three of the Liberty's life rafts that had been lowered into the water by survivors to rescue the most seriously wounded;
"4. That there is compelling evidence that Israel's attack was a deliberate attempt to destroy an American ship and kill her entire crew; evidence of such intent is supported by statements from Secretary of State Dean Rusk, Undersecretary of State George Ball, former CIA director Richard Helms, former NSA directors Lieutenant General William Odom, USA (Ret.), Admiral Bobby Ray Inman, USN (Ret.), and Marshal Carter; former NSA deputy directors Oliver Kirby and Major General John Morrison, USAF (Ret.); and former Ambassador Dwight Porter, U.S. Ambassador to Lebanon in 1967;
"5. That in attacking USS Liberty, Israel committed acts of murder against American servicemen and an act of war against the United States..."
The Moorer Commission