"Open source is great! We heavily rely on open source! We support open source! So let us maybe give you a key that lifts artificial restrictions from our proprietary code. Only if you're open source. Oh and you mustn't do exactly the thing we do: try to make profit with open source."
If I had made something Gitlab needs, they would not need to ask me to give anything for free because that's what I do by default. I don't build artificial scarcity in my stuff.
I assume you have a day job and in the course of your duties, you charge people for your time while working with open source frameworks. Would it be hypocrisy for you to expect a wage while building solutions based on other people's efforts?