It's not that bizarre. People generally understand that it's not the job of fiction writers try to write as realistically as possible, and when they criticize a lack of realism in a work of fiction, they're simply not copping to the truth. Maybe it's because the truth would embarrassing for them to cop to, or maybe it's just that they don't have the vocabulary to articulate what they're really trying to say. In any case, what they really mean is that they, for whatever reason, wanted to see him win easily, and they don't like that it didn't turn out that way, and 'realism' is a way for them to intellectualize a criticism that is, at its heart, motivated by personal taste.