Not all developed countries have legally mandated minimum wages, even those that are often considered "socialist" in American parlance. Indeed, Sweden is one such example!

(In practice, those places still have minimum wages - it's just that they're negotiated between employers and unions, and can vary across different industries and geographically where that makes sense.)

The real problem with min wage is that it's effectively a regressive tax, because it raises the cost of the cheapest produced goods/services - which, of course, tend to be disproportionally used by those who simply can't afford anything else. So you're taxing the poor to help the very poor! It is better compared to a free-for-all jungle, but it's much worse than e.g. UBI (funded by actual progressive taxes, on income, or better yet, on capital gains) without min wage.