I think the term fridging in comics is often misused, applied to any female character that dies and has a male character react. Damian was a very strong and well written character, with a good story and journey that ended tragically. His death does not detract from his character development.

If he were female, I don't see much that would have changed. Yet, the accusation of fridging would no doubt come about. Would it be valid?

I would say not because talia didn't like Damian as much as before. He didnt die to cause batman anger or to provoke him, batman was already fighting against the heretic and leviathan.