What I see in many Americans who become Muslims is the "convert zeal" that you see with many people who convert to any religion or sect? I think this is probably what you're seeing in your friend.
There's a lot of Xenophobia regarding Arabs and Muslims in the US at the moment which can cause a minor thing like this to be overblown.
That does not sound like good advice to me. The original post says:
I was looking around the site here and found the warning signs link which is very informative. It is also somewhat disturbing to me. I noticed that of the warning signs of people involved in a potentially dangerous group, my friend displays all of them.
It could be that you skimmed the thread and missed this line. In any case, if this poster says he/she believes all the warning signs seem apparent in the friend, that should be taken seriously. Thats what the warning signs are supposed to do - - point out specific issues that are symptomatic or otherwise indicative of a real problem.
Also, if I understand what you meant by "convert zeal", I'll point out that there is a mental state that might remind you of "convert zeal" that can be experienced by newly "brainwashed" people. I learned the term "honeymoon period" for it, and it's not zeal at all, it is a euphoric, psychological reality shift. Confusing someone's honeymoon period due to cult exposure with something like a harmless "convert zeal" would be counterproductive. Giving someone else an incorrect assessment in this area wouldn't be good either.