Obviously Punk agreed to do it. As you rightly pointed out, it takes two to tango.
If Punk was as "problematic" as people have suggested he wouldn't have agreed and would have most likely walked away (at least according to "dirt sheets" he already refused to lose to people).
The truth about issues like these is always in the middle. Yes, Punk is an asshole (that's already been established) but he's obviously NOT that big of an asshole to refuse to lose to Mox.
A lot of people on social media are too "married" to narratives. I was seeing some guy on youtube suggest that Punk went into business for himself in the match....and I was like..seriously???