The term 'Left Leaners' is a colloquialism for the political ideology of socialism, which is often associated with the color red. The crossword solution 'Reds' is a reference to this ideology, as it is a shortened version of the term 'Red Socialism'. This term is used to describe those who are in favor of a more egalitarian society, where the government takes a more active role in providing services and resources to its citizens.