they had to change the mining algorithm because they had no backing bitcoin has forked many time this is the same for all software this was just the first contentious fork. pretty much everybody supported segwit that why it could be forked so bitcoin cash is just the first that said fuck it we will go are own way.
The original bitcoin is always the longest proof of work with the hardest difficulty!
Like you have said before it is interesting to see it play out as both are taking a different approach to scaling I just wish twitter handles like btc or bitcoin.com would not try to deliberately miss lead people.
By original I will assume you mean "the real" Bitcoin. Let's remember this if the fork you prefer ever gets corrupted. Following that assumption, miners rule in other words and there would be no point objecting to their blocks or forking away from them.
But I disagree. There are more fundamental parameters to Bitcoin than the accumulated PoW.
Good to see we agree on something.