Is a corporation a slave? Many philosophers think so

In circles of occult technology, a corporation would simply be understood as an "Egregore". Which is itself might be considered a slave of its constituents, but no more than they are a slave of the collective will.

Am I a slave to my cells? Are my cells a slave of 'me' (whatever 'me' is)?

Lots of irrelevant mental gymnastics on the ethics of it. In terms of the idea of emergent behavior, I think this is well understood that companies have this kind of personality. Emergent behavior is also the cornerstone of the invisible hand.

This also extends to things like social networks. For example I think that Twitter the entity convinced Elon Musk to purchase it (so it could evolve as an entity outside of previous constraints it had, see also Wintermute), and doing so was an emergent action.

That looks like a weird exercise in anti-capitalist rhetoric. More of a performance rather than serious inquiry.