I agree. I think both the elected government and these monopolies are actively harming people. However, eBay's refusal to sell children's books with racist caricatures is not the vanguard of some effort by those power structures to consolidate power; after all, racist imagery has been used for centuries to consolidate power in America.
These companies don't operate on the same kind of logic as the courts do - this sets no precedent. Amazon and eBay could block the sale of any book tomorrow if they wanted to; they could have done it yesterday, as well. The real power these structures espouse is to get us bickering over children's books, rather than devoting our energies towards things that actually matter.