This is more applicable to liquidity providers or things like AAVE and compound where your crypto is actually loaned out. With maker, your crypto doesn't move anywhere and isn't loaned out to anyone.
For what it's worth, if you use AAVE or Compound, you also have to declare interest income on what you've earned.
With maker, you'd be responsible for capital gains if it was liquidated because you fell below the 150% minimum ratio.
Admittedly, I am not familiar with maker I will have to go take a look.
I guess the difference between me and someone who would use these DeFi apps, is that they are using crypto as a speculative investment (which is fine, I speculate with other assets all the time). But most people do not have a significant portion of their net worth in crypto tokens. For me, it is much cheaper/easier/safer to just get a traditional loan.
Once you include your exchanges fees in your cost basis, you actually lost like 30-40$, so it's a taxable event with capital gains loss.