No one is saying you can't criticise the manager as far as I can see? The comment was Ange can't spot talent because Spence had a good game and has been used sparingly by Ange. Now it's obvious Spence has talent, and I'm sure Ange would say the same. But you need more than talent at this level, and it comes down to things that we don't see - application, hard work etc things there has been talk he has not scored well with in the past.Yeah and people know more about tactics than Mourinho and Conte. Even that clown at Southampton knows more about football than all of us put together but if I were a Saints fan, I'd still want him out.
Same goes for Postecoglou: he's got a long career in football. So what? With that line of thinking, you can't comment on anything except maybe your job (assuming you're good at it) and a couple of topics you know a few things about.
It would be more convincing to argue that he was right to keep him out of the team (after all, he was injured) rather than question people's right to criticise the manager.
Then as you mention he has been injured - Now guess who has the best insights into all this info? Yes, Ange and it's not like the previous manager was playing him either . So I guess us armchair fan know it alls should really be swotting up on our coaching badges or offering ourselves as player scout gurus because it's all so easy for us, or maybe just maybe there is more to Spences lack of game time than meets the eye.....