I don't know when this protest thing happened, but one thing I do know is that this is one great article. It can be a bit offensive to those within particular industries, but the only reason I share it is because it points out a number of causes and consequences of minimum wage hike.
The points this article has made are economic in nature. The bottom line is that steep and abrupt minimum wage increase can potentially lead to:
1. Higher unemployment (more layoff, more replacement of human labour with machine, etc)
2. Higher price passed on to consumers (everyone) due to the increase in production cost
3. Loss of incentive to pursue higher level and more sophisticated jobs that can pay higher than the minimum wage (in industries like fast food) can
4. Due to point 3, a larger number of workers will be encouraged to enter into the fast-food industry (or any other similar industries that require lesser skill and education), creating imbalance within the economy. This can ultimately lead to lower number of people in higher education and lower number of those doing jobs that really matter like nurse, firefighter, teacher, etc.
5. It will end up causing dramatic wage rise across all industries and give rise to an unstable state of the whole economy.