Earlier quoted context omitted.
The idea is that it's not a conversion, it's a loan. The collateral is held in a smart contract and when you pay off the loan you get it back. In much the same way, people take out loans on their stock portfolios, and they don't pay capital gains either.
Is there any definitive source on this? I get lots of conflicting information from my brief google search. Equities and Cryptocurrencies are not treated the same for tax purposes by the IRS. It seems like they are treated as property and do not qualify as a "fungible" asset like stock or USD.
But to my amateur mind, treating it as property doesn't seem like a problem for this view. If you get a loan from a pawn shop, you're not selling them your property, you're just putting it up for collateral while you pay back the loan.