Back in the day, the western and sci Fi movie genres were looked at as fads and the old directors and actors jagged them and used to say they couldn't wait till this fad dies.
It feels the same now with these old directors who don't get it immediately dismissing it cause they don't understand it. They're doing the exact same thing that old directors used to do to them when they broke in.
Instead of just looking at a popular genre and saying "it's not for me" they have to bitch and moan about something they don't even watch. Cause frankly I highly doubt scorcese has ever even watched a marvel film while bitching about them