To be clear you don't need to have money invested/growing in order to retire. You just need money. Putting $50 in a jar is still $50 you'll have in retirement to spend on something. Nothing unethical about that.

But to counter inflation and sometimes just for the sake of wanting more, you can take an additional step of investing your money so that it makes more money. That passive income needs to come from somewhere.

If you invest in stocks, it's coming from the company's exploitation of its workers to generate profits (in addition to other rent seeking behavior; many companies own sizable real estate investments).

If you invest in real estate, it's coming from rents.

If you invest in funds, it probably owns stocks or real estate.

What you're really asking for is a way to generate passive income without exploiting anyone. But this is a solved problem. The answer is a government entitlement program that folks can pay into (i.e. Social Security). It's just been gutted by Congress. Did they remove the only general ethical option for investing for retirement? Maybe.

This isn't to say there aren't places where each of us feel we could put our money and have it grow without feeling part of something unethical. Maybe a local business could use an investment and be happy to pay back interest. Some folks are morally opposed to government bonds but I think they're fine as an option.

And thinking of investments outside of the box a bit can help too. Spending money today to upgrade or buy better things can itself have a future return on investment and be equally good of an investment strategy than putting money in a savings account.