Lots of stuff you can easily move past because, while you may not agree with the decision or like the decision, you at least understand why it happened. Peter Warrick and Laveranues Coles scammed Dillards to get free stuff -- you might not LIKE the behavior, but you can least understand someone wanting to get some free stuff when they're in college. Donte Stallworth killed a dude while driving drunk -- that makes most people upset and they rightly criticize his decision to drive, but most people can at least understand how someone drives drunk (and many, in fact, have experience driving drunk).
This, though, is really hard to understand. Making up (if he, indeed, was complicit in this fraud) a fake girlfriend and then killing her off to attract attention or publicity is just weird. Having an online relationship with someone, referring to her as the "love of your life," having never met her in person (if he WASN'T complicit in this and just got duped) is similarly weird.
It's a big deal because it's tough for people to understand why the hell he made any of the decisions he did in this case. When people don't understand why you did things, it makes it hard for them to trust you or view you as reliable.