Final answer:
Greeks protested in 2012 due to government economic policies that introduced austerity measures, including wage cuts and tax increases, following the Great Recession.
Step-by-step explanation:
The issue that caused Greeks to protest in 2012 was related to government economic policies. Specifically, the protests were a response to the austerity measures that the Greek government enacted as a consequence of the economic downturn from the Great Recession. These measures included cutting wages and increasing taxes to meet the requirements set by international lenders. This led to significant dissatisfaction among the Greek population, resulting in massive protests. This situation was different from actions taken by countries like the United States, which had more freedom in choosing their response to the financial crisis without the same level of constraints from international institutions.