Google Play is cool, but social isn't about features. It's about people, and the people are on Facebook. Maybe Google+ isn't designed to supplant Facebook, and maybe it shouldn't be, but it's hard to argue that it wasn't designed at least with Facebook in mind. Like it or not, Facebook directly stores and controls a tremendously large chunk of the data in the world, and to top it off it is arguable that it is this data is most important to people personally, since they spend so much more time with it than they do with, say, Wikipedia. Regardless of whether G+ is a direct Facebook competitor or not, this chunk of information is also off-limits to Google, and the result is that Facebook as an entity poses an existential threat to the entire company, whose job is expressly to make information accessible and searchable. Search isn't going anywhere, but if the most important information is locked away by Zuckerberg and Company, then it may also not be going anywhere especially interesting.
In spite of what I just said, I will grant that you're right when you say that Google+ isn't Facebook. The comparison is almost certain to be unflattering to Google+, and it misses something essential. In particular, regardless of what TC or any other pop-tech journalism firm likes to admit, Google did get one thing profoundly right with Google+. The ability to share blog-style posts in a more freely social setting has catapulted the site to popularity among a nontrivial portion of very prominent academics, not to mention the very influential tech people who use it. Facebook was the minority when it launched to ivy league schools, but one key to their success was that they had the attention of the right people. Google may not be popular, but that doesn't mean they're wrong. Time will tell what happens from here on out, but it will be ironic if the prominent hackers who jump ship because Google is changing ended up jumping ship so that a new set of hackers could build something cool in their place.
While I ended up agreeing with a lot of the points of the original TC article, I think your conclusion ended up being more right, and it is truly unfortunate that Google+ does not get defended as it probably should.