They had a very good opportunity thanks to shit facebook had done.
And they wasted this opportunity with silence.
Yes, that is really a shame.
I agree with your sentiment. Maybe they had already paid for these ads and couldn't cancel them. Who knows.
Well, hope for the better and probably everything will turn out to be fine and reasonable later.
As for me, I would rather prefer Sphere to be known for its distinct features as social media platform rather than capitalize on Facebook's blunder and I had high hopes they can do it.

That difference is what it takes to be something of a characteristic and I strongly support Sphere's attitude in this matter.