If a company is looking for an open source work in the candidate CV it means they want to know if that person is keen on providing work for free. It means that the candidate shouldn't have problems staying over time without pay because it is his or hers passion.

There is a distinction between passion and exploitation. You can be passionate without having to give away your labour for free. Big corporations want people to work on open source because it saves them R&D money. Some projects take years to develop and that costs millions had the companies had to pay salaries and taxes, but instead they can just appropriate the project once it is mature enough, pat the developers on the back and then make billions off of it without sharing a penny.

You can be passionate and develop your own business, own projects without having to share them and saving corporations money.

To level the playing field big corporations should be required to pay royalties to open source contributors.