Why should they? They paid their players millions of pounds a year, whilst keeping within FFP constraints, to try and get to that position and were pipped to the post by a team who seemingly bent the rules to gain an advantage over everyone else.
Imho if there is a case to be made then Steve Gibson should take it as far as he possibly can.
It is about time someone stood up to the EFL and Derby, where the sale of their stadium last season and the signing of Rooney this season absolutely stinks.