Yes, serial killers/serial killings and terrorists/terrorist acts are exponentially more despicable then the Benoit Murder/Suicide. No doubt about it. However, the one thing with those is that there was not just a story to tell, but something compelling about the films (I'm not condoning the actions, just saying that there was something that could be made into entertainment out of these heinous, despicable acts). People enjoy watching horror films, and enjoy watching stories of muderers going on killing rampages. The Chris Benoit story would be spending 90 minutes wasting time to go into 5 minutes of the Killings. Are you gonna tell me that's worth spending money/time buying/watching? Cause I'll say it isn't.
You really didn't just say that a movie about a pro wrestling killing his family and himself can be POSITIVE, did you? Abso-damn-lutely NOTHING positive can come out of this. All it does is dig up old memories that cast wrestling in the most negative light possible.
The biggest problem is, as I mentioned, the entertainment value of such a film. The aforementioned films all had a story that would be able to keep people in their seats for 90+ minutes. 90+ minutes about a professional wrestler (even if it shows him having issues) then him killing his family/self doesn't work.
Unless they change the story to have him kill his family, then a bunch of other people, then they can maybe make a movie. If they made a documentary, it WOULD work. If they make a fiction film and keep the story as-is, then their movie won't work, because there won't be anything compelling about it.