Blogs come under the catagory cms sites Because a blog is a type if content management system. Is it a blog yes. If I had to answer the question I would say it is a blog.
All blogs are technically a CMS. CMS stands for 'Content Management System'... So really, to define it as a CMS, you're just asking if there a system behind the site that manages the content as opposed to just static webpages. In this case, I'd say yes, that website has a CMS.