I had a blog and regularly commented on dozens of blogs from 2005-2015. Just about all of them used Google Analytics and in the early days many, including mine, were hosted on Google's Blogspot.
There wasn't any legalese on any of the smaller/medium sized ones and I really haven't once regretted that there wasn't.
My "why" question was intended from more of an ethical first principles standpoint than a legalistic one.
I know that some jurisdictions bury pretty much any online activity in mountains of regulatory requirements. That's not novel or interesting. As I said in the ancestor comment, it's "a sad state of affairs when even personal blogs are expected to be laden with legal documents".
I had a new website that had minimal text content. At first the most popular Google keywords were from privacy and terms! Had to change those pages to no robot.