Blogger/Blogspot and Spam Comments

I used Blogger for my previous blog, just before I moved to Github Pages, Jekyll and Disqus.
Having moved my blog here simply means I do not mantain the old blog anymore. Period.
Except when I do!

I published two particular posts in the old blog within the last years:

• a post about my new book on PostgreSQL Server Side Programming;
• a post about my new (this) blog.

Today I decided to have a look at my old blog, because it is raining cats and dogs, and because I don’t remember it anymore. And I saw 12 comments on my book post! WOW! I have to read them all immediatly!
But they were all spam of people offering me unlimited credit cards, bank transfers for free and some other stuff including females!

Clearly, even if the blog is dismissed, it is not a very good impression for the occasional reader to see such a lot of spam. Therefore I decided to reconfigure the blog to block comments from anyone and to show only the last two posts.

I’m curious about how Blogger cannot moderate on such spam comments, while Disqus apparently does its job. Of course, I’m talking about two different pieces of software: the former is an all-in-one blogging platform, while the second is a comment-only platform.