For hundreds of years, political groups have used language to maneuver around each other. One group, claiming the mantle of “ideological purity,” would become fed up with what they viewed as inconsistency or inaccuracy of the ideas of the main group and split away from it. However, they would continue to call themselves by the same name of the original group in order to preserve their credibility.
This kind of philosophical warfare creates confusion, often intentionally. Classical liberalism of the eighteenth and nineteenth centuries, based on small government and individualism, was gradually perverted into the modern, collectivist, government-obsessed liberalism we hear about today. The fracturing of the original socialist movement into dozens of groups illustrate the point just as well: you have Marxists, communists, Trotskyists, Chomskyites, Lenninists, Stalinists, Maoists, social democrats, liberal socialists, “libertarian” socialists, (misled) anarchists and anarcho-syndicalists, eco-/ethical-/religious-/regional-socialists, national socialists and blah-blah-blah socialists all claiming to be... well, true socialists. It's maddening.