I think Fauci is actually being pretty kind to Trump with that estimate, he didn't specify a timeline (no one can, obviously) and a lot of states, despite the terrible leadership by Trump, have started implementing measures to help mitigate the worst hopefully. It's ten/twenty times the actual present Italian fatalities, so per capita roughly similar but in the upper bracket to account for the tardiness of the response. It's a terrible number but still palatable to compare it to a very bad flu, yet high enough the current administration could hope to officially undershoot it before the peak passes.
I don't blame him for playing the game because that's apparently the only way you can bait Trump into common sense, but it's a very non-committal, political statement to make.