If someone got high result from that, it doesn't means that he is spammer. Personally I receive 98% good quality post and than what? I am spammer? No, I don't think so about myself.
Correct. That will likely be the case. Due to the variance in posting from genuine people, their percentages are likely going to be lower (e.g. mine was under 80% last time that I've checked it). Whether or not you think that you're a spammer is irrelevant.
I am in the same case. I was labelled as "excellent" and I feel that was pretty fair.
Nonsense. I've looked into your posts right now, and they are terrible (random 1 liners). This proves that the feature was completely misleading, ergo useless.