Perhaps their adamant, aggressive tone could be partly due to their frustration?
I've no doubt that some of the traders who post at FF are profitable, some immensely so. But I also wonder how many other successful traders bother to post on forums. I'm reminded of the saying "those who know, don't say; and those who say, don't know". There might be cases of that here.
I've become very careful in the way that I sift through information in public forums; I don't take anything for granted without proving its validity for myself. However, it's usually not too difficult to determine from the language in a post, as to how successful the poster might be. I see extravagant boasting as a symptom of ego rather than knowledge. If I was making huge amounts from my trading, I wouldn't feel the need to tell the whole world about it; I'd just smile quietly to myself as I watch the sun set from the balcony of my beachfront home in the Bahamas, LOL.