Wow, you are clueless, and you obviously just listened to some biased report.
The fact that Jonjo connects inside the right foot cleanly means he had some control. I can understand the argument of being slightly out of control, but that's at most a yellow card. His left foot is clearly on the ground. Far more on the ground than the Kompany challenge. Also, you completely ignored the fact that Evans made a worse challenge. He clearly jumped in two footed studs up. If you watch closely, his grimace actually comes from the force of his fall when his arse hits the ground. He's perfectly fine before that. By law, a two footed tackle must be a straight red card. I'm not really seeing where Jonjo's tackle was so dangerous other than the force he came in with. He actually did the necessary thing to make it less dangerous by coming in with the inside of his right foot. Evans came in straight with both feet studs up. In my opinion, Jonjo was the one in danger, but he came in hard enough that it didn't effect him. If I was the official, I personally would have allowed play to continue, because I feel Jonjo made a clean challenge. It actually took me a second look to realize that Evans committed a two footed challenge.
Kompnay winning the ball was never what I claimed against. He obviously wins the ball. He does make contact with Wishere, and his straight leg barely misses Wilshere. If Wilshere's leg would have been directly behind the ball, that's the exact type of challenge that can break someone's leg. That's why it should be a red card. It's afar more dangerous challenge than what Jonjo did. By the way, the commentators said at first it was a two footed, but they corrected it to what happened. They said both feet were off the ground which they clearly were. He made the tackle with his bottom leg, so the upper leg was clearly off the ground. Wilshere was just lucky he slipped, because that took his leg out of the way of the tackle. If it hadn't, I doubt we'd have been arguing, because Wilshere would have been crushed.
Kompany's quality as a defender was never questioned by me. I actually really like them, but this is a definite red card for me. Being as good as he is, he should have been able to make a better decision than to go into a challenge like that. Really, he probably didn't need to leave his feet. He could have just made a standing tackle.
Another example of a tackle that I find not quite as bad as Kompany's against Arsenal. This one is a bit two footed, but he clearly wins the ball without contact. He is also under control in my opinion, because the tackle is by designed to take the ball with the right, and the left foot is supposed to miss. Now, he does come in with excessive force in my opinion, and he does leave both feet. This should have been a yellow for me, because of excessive force.
http://www.dailymotion.com/video/xniymo_manchester-city-vs-manchester-united-kompany-red-card_sport#.UPbi9GfoDDs