No you're right. But you don't have to worry about it. It's rather a good news in fact, I hope it will be enforced heavily.
The idea is that you can be taxed ONLY if you sell the result of the fork. If there is a fork and you don't do anything with the coins then nothing is taxable.
How is it a good news? Well it decreases the incentive of a fork. Because tons of people won't get the new coins, knowing they will be taxed.
Hence less shitcoins and less forks.
So, having read the PDF, and noting that I am not a tax lawyer:
It all basically comes down to if you have control of the hard forked / airdropped coins.
If your BTC are on an exchange, and a hard fork or airdrop occurs where the exchange credits you the new coins... then you are on the hook for the income as you have control of the new coins in your exchange account.
If your BTC are on an exchange, and a hard fork or airdrop occurs where the exchange DOES NOT credit you the new coins... then you are in the clear, you don't owe anything on the new coins.
If your BTC are in a personal wallet, and a hard fork/airdrop occurs.. If you know about it and download the "new" wallet so you can have control of the new coins, again you are on the hook.. report that income.
If your BTC are in a personal wallet, and a hard fork/airdrop occurs.. If you are unaware of it, and never download the new wallet... It will prolly come down to how understanding the IRS auditor is.. either you owe it, cuz you *could* get control if you downloaded the new wallet, or you don't owe, cuz you obviously wouldn't download a wallet for something you were completely unaware of...