Nah, it's pretty true. Whedon wasn't given any credit before the movie came out (and was considered to be a big risk by most fans) After the movie came out, there was retroactive credit given to him for being "the right choice" and people suddenly thought his experience on Buffy "really prepared" him for it. But most of the applause came down to how shrewd Kevin Feige was for picking Whedon.
The creatives get to share success, at best, with the executives. In a lot of cases, people don't even know who wrote these movies outside of Shane Black and Joss Whedon. So the credit just goes to "Marvel" as a generic company.
Superhero fans have been trained not to applaud individual writers and directors, just like superhero readers are trained not to really applaud writers and artists. They're trained to give thanks and praise to editorial/executives for getting writers & artists to fall in line with their editorial mandate.
That's what's happening here on the film side, I feel. It looks like it's happening quite a bit. When Iron Man 3 didn't go right, it wasn't because Feige hired Black. It's because Black made a creative decision nobody liked. But when Avengers took off, it was because Feige was smart enough to know Joss Whedon was good with ensembles.
The credit is given to executives over the creatives actually making the movie more often than not.