How does google override a redirect from FR ?
They partner with the makers of browsers to be included in their programs (unless you turn it off). It can be a good thing I imagine at times, but they get it wrong on occasion. FR is a solid site, but I am sure they can link to a web site here and there that can be bad for your computer. If someone linked an article say from "Bad4UrComputer.com" and FR was found linking to that web site it could also be considered a bad web site. What we don't know is if AIM.org that they said FR linked to was actually a bad malware site. I would almost bet they are a good site that some liberals decided they wanted to mess with so they reported them.
I will post more in a bit. I found something earlier that I didn't post that perhaps would help others understand (or do better research than I am capable of).