How was that a red card for Ronaldo? Wow..
Just watched the highlights on local TV and all the commentators agree it was a red card. He pulled the hair of the player siting on the pitch. It wasn't all that obvious and I don't think he actually hurt the guy but nevertheless the referee behind the goal spotted it and it is a deserved red card.
In that particular game I don't think it was a deserved red card..
What about the guy kicking the Juve player in the face? That's not a red card however the one on Ronaldo was a clear one.. nah.
I don't agree with first part of your post. This Ronaldo incident falls under same category as punching or kicking the guy while he is down on the turf. The consequence for such unprofessional behavior should always be a red card followed with additional one or two matches ban. Granted it was more like half accomplished pulling of the hair but intent was there. If that was a start while they are fighting for the ball and ref had decided to let a rough game then I would probably agree with you.
Regarding second part of your post.... I didn't watch the whole game and highlights didn't show that particular situation. But if it was a bad start as you say it was then the referee should have given him the red as well.
I hope above was clear enough since English is not my first language and I did have few beers while watching a toothless performance by City.