I’m guessing they give you the option to show hidden messages for context when you see people replying. To me it seems like a nice balance of hiding the things you don’t want to see but still giving you the option of joining the discussion in a more in depth way should you wish.
Maybe ‘hide’ isn’t the right word, but it certainly makes someone’s posts ‘Opt In’ instead of just presenting them.
That said, you do what works for you, very clean solution.