This is from their FAQ:
"When you receive cryptocurrency from an airdrop following a hard fork, you will have ordinary income equal to the fair market value of the new cryptocurrency when it is received, which is when the transaction is recorded on the distributed ledger, provided you have dominion and control over the cryptocurrency so that you can transfer, sell, exchange, or otherwise dispose of the cryptocurrency."
You bolded the wrong part, so I underlined it. If you never split the new coins from the base chain, there is no tx recorded on the distributed ledger. And therefore, by definition, those coins have not been received.