"creating software for free that largely benefits large corporations"

Who cares. The end result of this is that we all get to use amazing software, often for free.

Think of your open source contributions as a gift to all of humanity. I wouldn't get too hung up on the fact that bad people can use it. Hammer makers don't add conditions on who can buy their products, even if it could be used as a murder weapon. Take solace in the fact that your work is creating far more good than evil.

You're increasing the rate of innovation in the world. And we're all grateful for it.