He knew it was, he denied it was wordspeak as he said it.
Fauci is a smart guy, but he's not the best spokesman if he's going to make statements like that.
That's the sort of stuff that causes FUD.
His point was that the virus moves faster than our ability to track it.
So, when you are acting to take steps you have to “assume” it is at point D, even though you are currently at point B.