Vince DOES own wrestling, he does!
No he doesn't he owns a Wrestling Company and perhaps even own the library and assets of the likes of WCW, ECW but just because he owns the #1 wrestling company in the world still does not mean he owns Wrestling. That's just egotistical for anyone to think, though I am not sure Vince thinks that way.
TNA, Mexican, Japanese, and even the independent promotions still exists and Vince doesn't own those. Wrestling is bigger than one company it's a legacy that's existed for over a century way before the WWE or Vince McMahon ever existed.
I went to a local wrestling event from a Japanese Promotion sure there were like only like 100 to 200 people but these are passionate fans. And this is not the WWE or Vince's promotion its just plain wrestling. And the fans loved it.
That said, so for cheering for CM Punk. Ultimately it's the fans choice. But I take this into another perspective. Why did fans like Punk, why do fans cheer for Punk, and how did Punk get so popular? Of course his ability as a performer is one major factor but I think it's because CM Punk "keeps it real". He doesn't mince words or try to sugarcoat things for the sake of his image, over the years Punk has been straightforward from his Pipe Bomb in 2011, to him hanging up on a radio interview, to his altercation with a fan on RAW, etc. Punk is a straight shooter if he hates something he hates something, if he likes it, then he likes it.
I guess that's the appeal of Punk over let's say Cena. Cena is a company guy and walks in the boundaries of company lines. Punk does not and that's the quality that fans like about him. If he tells you he's burnt out he will, if he tells you isn't happy sometimes being the WWE he will (as he did in that interview during the UFC weekend in Chicago).
That said while I am disappointed that Punk walked out and dissapointed in him, on the other side that's who Punk is. If he's frustrated he's not going to take it. That characteristic of Punk is what the fans like about him so why should we be mad at him now when he's just behaving the way we expect him to? Isn't that why we like him in the first place?
In the case of Punk it's pretty much "what you see is what you get" out of him and no smoke and mirrors. There's no wall between him and the fans and he's been proud of being transparent and honest (sometime brutally)
The thing I have to say about Punk though is that he walked out before Wrestlamania. That shows he's being "real" with how his actions, even Austin walked out only after WM (after he got his bonus). Basically Punk said, " I am pissed off in what's going on I am walking out and I don't care about the WM bonus pay" and he's had enough.