Whether you like Trump or not, it comes across as petty to jump all over him for a misstatement like this, even if it is hyperbolic. In all likelihood, some aide probably mentioned that "Google has 1700 engineers building a testing website", that stuck with him and he ran with it.
BFD, come on people. Of all the things to pick on at a time like this, we've got a lot bigger fish to fry.