That phrase that you said has absolutely nothing to do with the Linux/Libre philosophy.
You take care of your self and scratch your own itch
While I understand that you meant to make an analogy with people creating the projects they want to use, the vast majority of people don’t create their projects, and instead contribute to others, and they contribute with existing issues not necessarily things that they want or need. Alternatively you can see that a lot of issues are fixed by people who are not affected by it, it’s very common for issues to ask people to test specific changes to see if they solved the issue they were facing.
and you should not be a liability to the society
The vast majority of people just use the software that the community maintains, and when they need a feature they open a PR and let the community implement it. So the vast majority of people are a liability to the community, even if you contribute to one project actively you use several others that you’ve never contributed to.
but make your self useful and contribute back.
This has nothing to do with right-wing philosophy, in fact most right wing people are against any form of contribution,
And I think this is kind of the reason FLOSS works well, it can be aligned with many philosophies.
You might not like it, but FLOSS is extremely aligned with left wing ideology, where people contribute to the community because they want to and the community provides back without asking anything in return.