Alright so after watching Pluribus and some discussion online I have to say I don't necessarily think the hivemind's love is fake.
I think they fully mean it when they say they love Carol. They have the perspective of everyone on Earth! Including Helen's! But in the end that love is completely meaningless.
I'm not sure how to explain it, but basically the love they feel for her is no different than the love they feel for everyone else. How they feel about Carol doesn't change or evolve regardless of how she acts. (They even say that their feelings for her hadn't changed after she drugged Zosia).
By the end of the show, Carol thinks she has a genuine connection with the Zosia/the hivemind, but there is no connection. The hivemind doesn't feel any closer to her or any different for her after everything that has happened, only Carol's own feelings has changed.
