Wanting something isn't the same thing as thinking that it's owed to you.
Of course it's not.
But there are many, many people who's reaction is not just "aww, I wanted this, but got that...". That would be the reaction of people who are disappointed.
There are people who felt they were owed a certain type of ending, and now that hasnt come, they are demanding DLC to "fix" the ending, they are saying how they will not buy Bioware again etc... That is a reaction of people who feel they are owed something.
There's nothing wrong with being disappointed in what we got, there is nothing wrong with wishing they would change it. But at the same time lets not pretend that no one, at all, is of the opinion that Bioware "owe" them.