Remember that the 2008 financial crisis experienced by our neighbours to the south was caused by greed and dishonesty from Wall Street and U.S. banks, not by minimum wage employees. The real threat to our economy comes from the policies of big corporations and stock market speculation.
Raising the minimum wage to $15/hour would allow workers and their families to spend this money on goods and services, which would provide a big boost to the economy. Consumer spending has a much greater impact on economic growth than tax giveaways to the wealthy, who simply hoard their money.
Recent studies on increasing the minimum wage show that there was no negative impact on the labour market. That said, some fear blowback from companies if workers continually manage to receive pay increases. They could, for instance, threaten to mechanize production in order to cut jobs or outsource them abroad.
However, most minimum wage employees are in jobs that cannot easily be outsourced abroad. Bank tellers, railway workers, fast-food cooks, etc., need to do their jobs on site. Any jobs that could have been outsourced have already left!