rel=nofollow is a HTML attribute value used to instruct some search engines that a hyperlink should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring in the first place. The nofollow attribute value is not meant for blocking access to content or preventing content to be indexed by search engines. The proper methods for blocking search engine spiders to access content on a website or for preventing them to include the content of a page in their index are the Robots Exclusion Standard (robots.txt) for blocking access and on page Meta Elements that are designed to specify on an individual page level, what search engine spider should or should not do with the content of the crawled page.
They need to remove the nofollow link on most blogging code now, it was used back in the day to combat against spammers but now most blogs have great spam protectors like Askimet.