Personally I blame the people who egged Brenda Leyland on. By the look of it this person was a lonely woman, twitter brought her the company she craved, she found her niche with people who gathered in a large group to mock and torment the McCann's. Brenda knew what she was doing, she was a woman in her sixties, an intelligent woman, no one made her do it, but she gained power from those who slapped her on the back and so she continued doing what she did.
Debating the McCann case is one thing, opening up facebook and twitter for the sole intention of whipping up hatred for other people is another.
I find the people defending the McCanns very short of arguments. Tell me please who was egging Brenda on? Of course, in your mind, it could not be because she decided for herself, after seeing all the information and the police files, that perhaps all was not as the parents said it was. How did she mock and torment the McCanns? She never sent them any personal messages. All she did was express her own opinion that some might find offensive but that's tough luck. Certainly not a reason to be pushed to committing suicide.
As for debating the case, that is something that the McCanns do not want at all, they are afraid of debates and different opinions.