Fixing problems as they appear is unethical? Ok then.
You realize, there are people who think differently? Some people would argue that if you keep working on problems you don't have but might have, you end up never finishing anything.
It's a matter of striking a balance, and I think you're way on one end of the spectrum. The vast majority of people using Julia aren't building nuclear plants.
Fixing problems when they appear is ethical.
Refusing to fix a problem that hasn't appeared yet, but has been/can be foreseen - that's different. I personally wouldn't call it unethical, but I'd consider it a negative.