"Why does it matter who wrote it? It's the message that counts!"
I'll tell you why. I'll tell you the same reason that George Carlin himself would have told you: because just swallowing stuff because it's wrapped in a sweet turn of phrase without examining it and really thinking about it makes us sheep and is detrimental to society. If you don't use your brain to filter what you accept as truth, you may as well not have a brain.
This phenomenon is a scourge of our time. The Internet makes the dissemination of information so easy, which is a wonderful thing. But it makes the dissemination of misinformation and disinformation just as easy, and that can be lethal.
The ubiquity of media and the ease of communication by any and all makes it more important than at any time past that we think critically, filter scrupulously, check sources vigorously, and pause for a minute before we hit that 'forward' or 'share' button. Failing to do so leaves us open to every slick con man, every polished politican, and every silver - tongued televangelist that comes along. Your credulity is the oxygen for their fire, a fire that will consume your money, your time, and even your freedom.
Yes, it's just a stupid chain letter. But how people react to it, and what they do with it, couldn't be more important. It matters.