We learned that Israel was going to strike, so the US decided to jump on board. Do we know how long of a notice Israel gave the US? What you're attributing to as a thought out plan of attack seems to imply plenty of time. I don't think it's unreasonable for Israel to have learned of the meeting with little notice, deliberated internally for however long, and then told the US about it with not much time. I could totally see where under current Pentagon leadership, three clicks would have been the reaction. Yes, the US had been saber rattling and building pressure. That's probably part of why the Iranian leadership decided to meet. Whatever plans the US might have had went out the window when Israel called up and said we're striking now.
May I suggest a better approach to that situation?
Israel: Hey, we're gonna start bombing Iran in 15 minutes, so pick your targets! Time's a-wastin'!
US: We do not give a fuck who is meeting with who when. If you ever want to see another dime, or another spare part, or another kind word, let alone have us actually do anything, then you aren't gonna do jack shit unless and until we're goddamned good and ready. Otherwise, have fun with the blowback.