No, you are wrong.
The taxable amount will always be the same. The only change was when you had to pay it.
If you bought bitcoin for $1,000 then when it went to $20,000 a few years later you bought some ethereum, that was not a taxable event prior to the new rules. However, you still had to calculate that into your cost basis when you sold the ethereum for fiat, so you would get taxed on all those gains at that point, when you converted to fiat.
Under the new rules, you get taxed on the bitcoin gains when you buy the ethereum, but when you sell the ethereum for fiat 2 years later, you DON'T have to calculate the bitcoin gains into the cost-basis of the ethereum. So your taxable amount would be much lower at that point.
The taxable amount comes out to the exact same amount to the penny under both scenarios.
The only difference is whether you pay a higher percentage or a lower percentage if you sell for gains within a year of purchase. So in that instance, it is a tax increase. But it is not an automatic tax increase for every person who trades alt coins on exchanges.