Why is it a lack of respect, when culturally in football it is the "done thing".

Like at cricket the "done thing" is to accept the decision. And also the done thing is to shout at the umpire when you think a batsman is out. Is that disrespectful? Thought not.

Like somebody said above, a good argment with the referee should influnce future decisions, therefore your actions will have a positive impact for your team at some point in the game.