I've wondered for a long time why Communism (and/or Russians in particular) were historically associated with the colour red. The best I can find is that the Russian army used red in its uniforms. But that itself raises the question again - why red? I realise that the idea of camouflage is fairly recent, and so obviously they weren't going to be outfitted in khaki, but why red? Aren't red dyes relatively expensive (relative to undyed material)? Relatedly, is the association of The Good Guys (tm) in video games etc with the colour blue purely a reaction/opposite to the red?
Sorry for my long-winded rambly question. I couldn't see it on the FAQ but have wondered about it for a long time.
The color red has an association with left-wing politics that goes far back into the 19th century, but mainly its use by the Paris Commune (1871) turned it into a Communist symbol.
It has nothing to do with Russia specifically. When the Russian revolution and civil war occurred, the communist forces formed the Red Army out of the then-disintegrating Russian Imperial army, and named it so because they were communist. The anti-communist forces took the name of the 'Whites'.
Neither side in the Civil War had particularly uniform uniforms, but they were mainly the same green and grey uniforms that the Imperial Army had had, which itself wasn't very different from other WWI armies in terms of color.
To answer the red dye question, there are some expensive dyes and some cheap. But, there are many different ways to achieve red. Crimson/cochineal is more expensive than madder root, for example. A madder red is a little more orange. There are many advances in making synthetic dyes starting in 1856, so the cost factor is quickly lost. Un-dyed textiles aren't used often in uniforms for a number of reasons. Above all else, it just doesn't present a very grand look. The natural color of wool, drab, varies by sheep (less uniform) and looks fairly dirty. One of the only uniforms that used un-dyed fabric were the unbleached linen hunting shirts worn by the very early Continental army in the American revolution. Although, some were dyed with logwood or had red contrast cuffs and collars. That was simply because the army couldn't afford and/or couldn't find enough of their desired red and blue wools for traditional uniforms.