Is it illegal to "diagnose" people without any kind of license on a website even if you provide a disclaimer?

A friend of mine recently directed me to this site:

http://www.anxietykeep.org/index.html

Now, it says that one of the goals of the website is to provide a diagnosis. While a disclaimer may say that the site is not responsible for its users, isn’t the owner still held accountable for offering to diagnose anyone without any sort of license?

I understand where this guy is coming from, but it seems like he would be doing more harm to those who suffer from any form of mental illness.

I’m just curious about this situation and want to see what others think. I’m not looking to bash the website or anything of that nature, but I do find it a little unsettling that someone who hardly has control over their own mental health (as made apparent by his Facebook) would provide services to those who should really seek professional help.