There were plenty of Packer fans saying it should have been an illegal hit and Barr should have been penalized and fined and suspended and flogged and drawn and quartered. OK that last one I made up but I am sure there would have been some in favor of it. With the rule being interpreted as it is now it would have been so be careful what you ask for.
Keep in mind the last two penalties on Matthews were not for late hits. They were for landing with your full body weight on the QB and/or driving him into the ground. I can't say I have seen the driving him into the ground used on the most recent one but it was for the hit against Cousins. What we are seeing is exactly what many people were asking for to have been called against Barr, that being driving him into the ground and landing on him with his full body weight. Not everyone, certainly not me, but if you can honestly say you didn't see anyone calling for Barr to be penalized you didn't read much. Now you will say sure they wanted him penalized but they were not calling for a new rule. Well he wasn't penalized because it wasn't deemed against the rules so if you wanted him penalized you need a new rule. You can't have it both ways. You can't want Barr to be penalized for driving the QB into the ground and landing on him with his full body weight and think what Clay did was fine.
Don't get me wrong, I can see plenty of differences between the two plays. The biggest being the distance between the QB and the tackler when the ball was released. On both of Matthews' hits, well this last one anyway, there is no doubt that Matthews landed on him with his full body weight just like Barr did. Some fans are just trying to figure out a way to say the Barr hit was illegal and the Matthews hit wasn't.
I read somewhere that the no landing with you full body weight rule has been around for quite some time but was never really enforced. It was just made a point of interest this year.
Full disclosure I didn't think the Barr hit, the Kendricks hit or either of Clay's hits in week 2 or 3 should have been illegal. If I had a chance to see all of the 39 or so RTP penalties called thus far this season I probably would not think half of those should be either.
A side note, and I can't recall where I read this to give proper credit but it wasn't me, I actually prefer the new rule to be called the Barr rule as it bars a defender from sacking the QB without getting a penalty