BTC hard fork for dummies

[RobJ]

I am new to cryptocurrencies and trying to learn as fast as I can. I generally understand the hard fork and also somewhat the two sides of the argument for/against. But, in that the hard fork HAS occurred, can someone explain why (or to what end) some exchanges/wallets are refusing to accommodate the fork and to support BCH.

Not trying to restart the discussion as to if the fork was good or bad for BTC...just trying to understand how an exchange or wallet is serving its customer base by not supporting BCH now that it is here and REAL. I understand I can move, for example, my private key from my wallet that doesn't support BCH...to another wallet or exchange that does...and voila, I would then own BCH, right?

And I understand that, for example, an exchange that was against the fork can be unhappy that the fork occurred. But, since it DID occur, what does it gain by continuing to stand against BCH? Let's assume that BTC IS harmed in some way due to the fork...could the fork be undone if somehow BCH is "killed"? I don't think so...so, correct me if I'm wrong, but the fork is here to stay...so what does an exchange or wallet hope to accomplish to stand against BCH?

I short, I get there were many against the fork, but the fork has occurred and won't be undone...so what can be gained to stand against BCH at this point.

[rizzlarolla]

"the hard fork" was not a "Bitcoin" hard fork, but an altcoin forking "away" from the Bitcoin blockchain.
I could "hard fork away" from the Bitcoin blockchain, with little to no hash power, creating "my new Bitcoin blockchain".
But that is not a "Bitcoin hard fork" either, or do you think my chain should be listed too?

For Bitcoin to "hard fork", hash power must compete over the same blockchain.