Well first of all, it's a repack. That alone is enough. He's taking other people's files are creating his own installer of it. This is completely unnecessary when people can just download the original, untouched files. I have heard that fitgirl cuts game content and deletes files to reduce file size. Again, this is completely unnecessary. Not very many people have such low download limits that downloading 2GB less is going to make a significant difference.
Second, "fitgirl" is manipulating people using the oldest trick in the book, pretending to be someone online to gain the trust of gullible individuals. By nature, you trust females on the internet more, without even realizing it. You can't trust someone that goes out of their way to get everyone to know he is a "girl." Even if he was a girl, no one would go to such lengths without reason. It is manipulation, regardless of actual gender.
And regarding keygens and trainers, there's a reason they set off false positives. It is because they act like viruses. Injecting into exes, for example. So, what reason would fitgirl's setup files have to act like a virus, I wonder?