That is definitely a reasonable position to take. Nothing would be worse than your Bitcoin being liquidated for some silly dollar loan. Stay humble stack sats is always a winning strategy. I would never borrow more than 20-30% LTV to avoid this problem and I don't plan to do so for quite a while.
As far as the ethical question goes it is true that you are benefiting from the corruption of the fiat system. However, I see this as no different from any other trade. Is it unethical to buy something when it goes on sale or to sell something that is highly demanded? This is how markets and price discovery functions.
I also believe that the more people who borrow dollars and save in Bitcoin the more we accelerate the downfall of the dollar and bring about hyperbitcoinization.