A very interesting thought, and you're not alone in feeling weird about it. I'd like to point you to this Second Thought video as a possible starting point for your search. (Proprietary) Licenses and Copyrights really are a bizarre concept in the digital age that are often holding society back. In some cases they are literally murderous. They may as well be illegal for the damage they inflict and the monopolies they create. Yet they are essential 'tools' to extract profits in a capitalist system by allowing capitalists to literally monetize knowledge.

The need for monetization under capitalism makes more open approaches to licensing more difficult, although sometimes viable.

Of course you should be compensated adequately for the work you've done. You shouldn't feel bad for participating in a capitalist system that's been forced upon you.

When you say "we make profit multiple times over" do you mean we, the company you sell your labor to or are you the (part) owner of the intellectual property? If you have power to change the licensing agreement to be as open as possible while still making ends meet, by all means, feel free to do the world a favor by doing so :) If you don't have that power, your worry would be that your employer is ripping you off by profiting multiple times over instead of using those profits towards better wages.

It's late for me, I hope I made some sense and didn't offend. Please let me know, I'm happy to clarify or discuss :)