Are Bitcoin and Bitcoin Cash two sides of the same coin?
no!
Some folks have accused the two cryptos of being part of the same incestuous family of elites - supporting different narratives for the purpose of a common or single goal.
there are a lot of weird theories out there and mostly they exist to undermine bitcoin and bring it down to their own centralized level.
i do believe that you are wrong about bitcoin and if some day i find out that i was wrong i will sell my bitcoins and move on because i am involved in bitcoin only as long as it has certain attributes and most important one is the decentralization which is why i stay away from certain altcoins such as bitcoin-cash.