Everyone in the fandom plays a game of pick-and-choose your canon.
There is nothing wrong with that. Batman was introduced in 1939. There are 80 years worth of canon for us to sift through. Probably dozens, if not more, writers with just as many interpretations of his character. As much as we loath to admit it, if it’s been published by DC, it is canon. Calling his character “wrong” is fine, it’s what we do as fans, judge and review what we’re given, but DC published it. They endorsed that interpretation. They are saying this is canon. And they do the same with the many, many characters that have come along within the franchise.
My point is, all of these interpretations are valid, regardless of our own personal opinions. So yelling at a fanfic writer because you don’t like how he or she is interpreting the character, when it’s been based on one of the many depictions of it in canon, is ridiculous.
We all play the game of pick-and-choose. We have no other option, because it would be impossible to write Bruce exactly like every single depiction of him ever offered within the pages of a comic book. Or on the screen. Or in a book. He’s a character with many versions of himself, and each one is ‘the real’ Batman. And the same applies to every other character. Dick. Jason. Tim. Damian. Talia. Selina. Stephanie. Cass. Barbara. Jim. The list goes on and on.
Just because someone has picked different canon from you, doesn’t mean you should yell at them. Or criticize them. Or ‘correct’ them. Bruce is both a good dad and a horrible one. Talia is both a good mom and a horrible one. It just depends on which canon you choose.
This post is perfect. This holds true for marvel, too- I can't tell you the number is times I've shivered in my damn socks writing fic because I feel like someone's gonna barge into the comments trying to "correct" my interpretation of the character.