.xxx Domain name not blocked

Hi, we run windows 7. I was surprised to find out that Norton Online family does not block out all of the .xxx domain names outright. Many of the .xxx domains are indeed blocked since they fall under the pornography category, but not all. One of them is xxx.xxx which is a large directory to many other .xxx sites. And some of the sites linked from xxx.xxx do not come up blocked. Two examples:babehub.xxx, playhub.xxx . Other miscellaneous examples: site.xxx, about.xxx . Those last two merely explain the .xxx domain name without any explicit material. Although, I don't understand why the .xxx domain is allowed at all.

 

Thank you for your time,

Keves