I agree, they are being way to harsh on it. Titanfall had almost no story or co-op modes, and a multiplayer mode missing basic features like private matches a launch yet got way better scores!!
And it's not like you are paying more for Destiny either. Destiny easily gives you 50-100 hours of fun if you really get into it, and its not like they are charging you a fee as a MMO would.
Now I'm not going to pretend that Destiny is perfect, but it is a far cry from the poor reviews it has been getting!
Here is a list of my pros. and cons for the game.
+Diverse enemy types
+Good loot game
+Lots of fun Co-op activities
+seemless conection to other players
-frustrating chat system
-no private matches
Because Titanfall was never hyped up as anything more than an incredible MP experience and no one was expecting anything more than an incredible MP experience. Which is exactly what was delivered, which is why it scored well. Despite, as you referenced, a lack of some pretty basic features, since the game was rushed.
Destiny wasn't rushed, and the main difference here is that at its core, Destiny just is not designed well. The good thing for Bungie is you can take a look at vanilla launch Diablo 3 and the Diablo 3 we see today and see that updates and patches can fix terrible design decisions.