It would have made sense if they did it just for the first month, to highlight the new strikes. But now I think it's simply laziness. I'm not sure how much effort has to go in modifying the strikes to include the Taken, but Bungie clearly deemed it too much.

One simple reason... Whether we wanted it or not, we've stepped into a war with the Cabal on Mars. So let's get to taking out their command, one by one. Valus Ta'aurc. From what I can gather he commands the Siege Dancers from an Imperial Land Tank outside of Rubicon. He's well protected, but with the right team, we can punch through those defenses, take this beast out, and break their grip on Freehold.

To stop year 1 players who didn't buy ttk from playing with the paying players.