I read it like his contract was something along the lines of "20 million plus a share of the profits." He isn't demanding $70 million, he's just hoping it will be a big success again.
Exactly, which is why I am kind of scratching my head at this whole argument.
RDJ, when he set up his contract, put in a clause where he gets part of the profits of the movie. Many actors do this. He is not asking for them to shell out 70 million whether the movie is a hit or a flop. This is why, in hindsight, Marvel is rather peeved with him. He took away 50 million from Avengers and so far has gotten 35 million from IM3 due to this clause. He is "expecting" that when the dust clears on the Avengers sequel he will likely walk away with 70 million, but it's only an estimate.
So let me ask you, what do you expect RDJ to do? Tell Disney/Marvel he is fine removing his profit clause from the contract if the money goes to his cast mates? Yes, because Disney is so well known for honoring everyone that works for them. Maybe have him just make nothing but profits and give up the millions he signed up for as a base salary? Okay then, what do you expect RDJ to do if out of nowhere the next Avengers turns into a commercial failure? He just gave up a very high paycheck for something that turned into a gamble. Will he still make a lot? Yes, but why should he give up his own money because the company paying him wants to be cheap with the others?
All he can do is use his "star power" to fight for the other actors to make more money. He never had to do this. He could have sat in his trailer, sipping million dollar frosty frappachinos, and not gotten on the bad side of Disney/Marvel for a bunch of other actors. Yet, he did, and possibly hurt his own chances for continuing his million dollar goose egg now that his contract is up. I don't consider that douchy at all.