Actually the issues are closely linked. For example, look at the Davis-Bacon Act which according to the National Center for Policy Analysis "the 1931 Davis-Bacon Act, requiring ‘prevailing’ wages on federally assisted construction projects, was supported by the idea that it would keep contractors from using ‘cheap colored labor’ to underbid contractors using white labor.". Similarly in 1925 British Columbia passed the Hours of Work Act to stop "Oriental labour" from competing with whites. Minimum wage (or Basic wage) was enacted in Australia for the same reason.

It was also praised by progressives at the time. Harvard’s Arthur Holcombe said that these laws “protect the white Australian’s standard of living from the invidious competition of the colored races, particularly of the Chinese.” Florence Kelley said that the laws were “redeeming the sweated trades” by preventing the “unbridled competition” of the unemployable, the “women, children, and Chinese were reducing all the employees to starvation”.

There was a time where we understood the economic impacts of so called minimum wage. We knew that it made it illegal for low skilled workers to be employed. Fast forward to today, if a homeless person cannot produce at a rate of $13.00, which is San Francisco minimum wage, they are not allowed to work. It's against the law! So though it might not solve every case, it would surely help if it were legal for them to hold a job.

http://www.forbes.com/sites/carriesheffield/2014/04/29/on-th...

https://www.quora.com/Is-the-claim-that-minimum-wage-laws-ha...

http://halifax.mediacoop.ca/blog/theuncivilized/31240