Yes, but me drawing a different line then you, or you drawing a different line than a third person, don't require cognitive dissonance on anyone's part. Different moral standards across people or groups isn't cognitive dissonance, different moral standards held by the same person can be - emphasis on can, since I think it's odd to presume the mental state of literally everyone who watches wrestling.
Benoit's a particular case given his wrestling and wrestling style draws a pretty clear line to his mental decline and ultimately what he did, which has been discussed here before. Not that I expect you to go hunting old posts on the topic, just saying that Benoit is an exceptional case for the heinousness of the action and how clearly his in-ring work connects to it.
Right, that sounds like it could be dissonance, just making sure we're talking about the same thing. I think we're prone to saying "it's cognitive dissonance!" when someone makes an apparently contradictory stance or/action, but we're reading it from our outside perspective, presuming some sort of hypocrisy, then prescribing a mental state.