Nice...How this can be neutral? ROFL
A lot of these type programs are first generation apps. All they can do is look at the surface of what is written, and attempt to rate things based solely on the words used. Much like profanity filters, they lack the capacity to understand user context.
Two friends talking:
Friend One: "Man, I can't believe I failed my class! I thought the exam was tomorrow, not today. I completely missed it."
Friend Two (sarcastically): "You're such a genius!"
Those statements would be neutral for friend one, but positive for friend two. Normally, calling someone a genius is positive reinforcement, but in this case it's sarcastic. These programs react to words used, not the context of which the words are used. They're cute to play with, and maybe someday they'll inspire someone to go the extra mile and sort out the nuances of subtle context, but as they are now, I wouldn't depend on them for any sort of diagnosis for my mental state or anything. (And I have seen some people who attempt to do that with journals which grade their writings. "You are 87% positive in your daily writings...")