They might be right that critics were gunning for the movie from the start, but there have been plenty of instances where critics turned around and actually praised a big Hollywood blockbuster if it ended up being, you know, good
Titanic got an 88% RT score, and the first Pirates a 79%, and people ridiculed the hell out of those movies beforehand. And the third sequel
of the Mission Impossible franchise got a 93%. And Avengers a 92%. And those movies are all about as blockbustery as you can get.