It means the minimum wage hasn't kept up with inflation. If people because of status or lack of skills are willing to work for low wages, this depresses the need of employers to hike their wages for our domestic low skills labor pool.
sure, that doesn't really help the low skill domestic labor pool (and the lack of a social security net makes it worse in the US), but in some cases, it might help the economy overall (at the expense of the low skilled domestic workers) e.g. in your example, by reducing the inflationary pressure of the minimum wage.