There are certain criteria that are required for something to be treated as a split and IIRC coin forks were really iffy in this case. The usual case in a stock split is that you get either more of the same security or something of similar likeness (a non voting class of shares in the case of the google split), which is arguable in the case of crypto.
You could argue it’s a split to save money and if you had a huge amount in BTC at the time of the split it’d be worthwhile. My tax savings were going to end up being trivial so I went with what was “safe”.
Edit: noticed your comment about Apple stock “moon”-big. If we’re reporting the fork as income then it’d be income at the value at the time of the fork. So if you had one BTC then the BCH income would be $277 or so and that would become the cost basis going forward. I didn’t have a lot of BTC so the actual tax cost was very low. If you’re holding thousands of BTC at the time then the story would be different and you’d be incentivized to argue a different tax treatment.
Apologies for the wordiness here!!
https://www.investopedia.com/ask/answers/052115/why-are-some...
if you dont bother to define the rules of the game then you're just pretty much barefacedly just abusing your legal power to tax whatever you want to tax for the sake of taxing.