Basically, people believe the first thing that they hear, even if it's false, and it takes a lot to prove otherwise.
My first hand experience was with my last big break-up. There was some extracurricular fucking going on before she dumped me for the other guy. We were renting an apartment before that. She asked that the lease be in her name so she could build credit. I agreed; but, she was really bad at keeping track of finances. There were times when she would have more than $5,000 of uncashed checks from me on her nightstand for our rent and bills.
So, I guess she could say that it was true that my share didn't hit her account for months; but, after the breakup, I finally cut ties with her entirely and a few mutual friends started coming at me telling me that she was justified in her actions because I wasn't paying rent. That was false. She was lying. I could have shown people my check book; but, they wouldn't have believed me.
This hit me pretty hard. It wasn't that long after that a friend was in a similar situation. When she asked me for advice, I told her to talk. I told her to share what happened with everybody that she could as fast as she could. I made the mistake of not talking to people about what happened until after everything had collapsed. I didn't want the same thing to happen to my friend.
Still, the problem is mostly with the fact that people do tend to buy the first thing that they hear. In the broader context, we all should be better at understanding that people lie and get shit wrong on a regular basis and that we should be receptive to new information. No matter how thin the pancake, there are always two sides.
I maintain that it's good advice, if you're going through a period of conflict, to talk to people about it and nip that whole thing in the bud. Still, the media should understand this phenomenon and be more responsible rather than just trying to be first all the time. What's more, the fault dear Brutus is not in our stars, the fault is in ourselves. We're all guilty of this. We all have the tendency to take the first thing that we hear and run with it. We should all be more cautious.