Do you reject volunteering?
Do you reject volunteering for non-profits? What about non-profits that have some paid employees? What about for-profit companies that you believe have a net positive effect on the world? What about jobs that you think are fun, I dunno maybe white water guiding, that happen to be for for-profit non-benevolent companies?
The whole idea of "you shouldn't work if you're not getting paid" is a category error.
If you want to do work, do it. If you're getting paid, great. If you're not getting paid but you want to do it anyway, great. If the only reason you want to do this work is because your current alternatives suck, well, I'm sorry to hear that, but you should still pursue your best alternative, which may be working unpaid overtime.
Mind you, in some cases, it makes sense to say "because I am part of a bargaining collective, I will eschew personally-beneficial options, as part of our collective negotiation strategy". Respect! But that's only sane if you're actually part of a bargaining collective. It is (usually) completely idiotic to imagine that you have solidarity with other people who do not see themselves as having solidarity with you.
All of the above comments are super generic, because moksly made some very generic comments, including "never work for a company for free", and I think moksly's advice, when taken as written, is utterly wrong. Now, specifically in the case of working paid or unpaid overtime, as with any other question about workplace environment or about compensation, the only reasonable thing to do is ask what your alternatives are, both short-term and long-term.
Tell me, if you're against overtime being the norm or a regular thing, what advice would you give to a hypothetical person who has no known alternative employment and a dependent to support, and who knows that their boss could hire others to replace them? Would you honestly say to them "never work for a company for free"? Surely instead you would say "do what you gotta do, and also btw try to find a different job, and also btw good luck buddy I feel for you".
The sentence "never work for a company for free" is utterly wrong-headed.