Anyone who learns enough vocabulary to be something resembling fluent (say, can comfortably watch tv shows or read books in that language), will be good at grammar far before they learn the 10k+ words they need to know. You can't consume enough of the language to acquire that kind of vocabulary and not have a decent intuition for the grammar.
I don't advocate ignoring grammar, but you really just need awareness of the basics, not to spend time doing drills or filling in blanks.
What really jumped out at me in your comment is that its definition of fluency (watch tv shows, read books) focuses on comprehension and appears to completely ignore being able to produce anything in the target language.
I don't advocate ignoring grammar, but you really just need awareness of the basics, not to spend time doing drills or filling in blanks.