The FAA fucked its reputation in three days, but this was a VERY good thing. It was a completely compromised body for years, and their behavior on the 737 Max is what alerted the world and the public to this fact. If they had grounded immediately, they would have preserved their unearned reputation to the detriment of long term aviation safety.
Remember the 737 MAX has both FAA and EASA type certificates, issued separately.