Sorry mate, you can bluster all you want about the quality of the NRL's administration (and be right) but the hip drop is a very specific type of tackle. It was recognised as such and the league agreed to stamp it out. The issue lies in the refs not understanding (deliberately, I'd say, in some cases) what it actually is and "enforcing" the rule as it suits them (Preston's alleged "hip drop" at a pivotal moment in the game).
Murray's tackle just wasn't a hip drop. This whole call out is just age-old fan behaviour, trying to call out double standards because we lost. You can legally tackle a player around their hips/legs from a kneeling position. That's what Murray did. He only left the ground because there was another player in the tackle and Preston's momentum dragged him off his knees. In that split second, Murray's weight was hanging from Preston, which sucks, but it was incidental and this is a contact sport FFS. All I want to see is a fair and impartial implementation of the policy. They got the Murray call right, they got the Preston call wrong. Pretty standard shit from the refs right now.