I completely reject your assessment, e. Israel is not faux anything, it is as real a nation as any other you care to name, including the Arab nations founded by the same Mandate system that offered land to Palestine's Jews to form their own nation. (And Palestine's Arabs to form theirs, an offer they rejected in favor of invasion and war.)
If Israel was founded by "terrorists," so was every modern nation, including the United States.
The King David Hotel bombing did not occur in a vacuum. The British Army was at war with Palestine's Jews, hanging, murdering, and labeling them as "terrorists" because the British Foreign Office favored an Arab takeover of Palestine in order to curry favor for Arab oil rights. The King David bombing was part of that long-running war. I condemn the King David attack because of its civilian nature; Irgun should have bombed an Army barracks, which was fair game during wartime.
That said, Irgun agents called British authorities to warn them to evacuate. The Brits ignored the call. Irgun then called the hotel, which didn't evacuate, and then called a news agency, which notified British authorities but not in time. Terrorists do not warn their targets. Irgun tried.
Nation-building is bloody and ugly and innocent people too often pay the price.