You make some statements which are true, but most of it is false.

An altcoin is something which is not Bitcoin. What is Bitcoin then? That's what the design paper explains.

You can't simply rely on hashpower, number of transactions, market cap metrics, popular opinion etc, or else any coin could be Bitcoin if they just gained those metrics.

"Bcash" is an orchestrated attempt at confusing users. The fork is called Bitcoin Cash, so why not use that name? The name was after all chosen in order not to confuse uninformed users more than necessary. Otherwise it would have been called Bitcoin straight out of the gate.