Social Democrats used to cover all of modern day anti-capitalist forces. Lenin himself wrote of him as a social democrat.

But with time they became ossified, began to enjoy the access to the state as union leaders or elected officials, many also tried to rectify the anti-imperialist slogans with the material benefits enjoyed from exploitation.

Around the First World War, the original leaders of the social democratic movement died and were replaced by right-deviationists, ultimately leading to the break with actual socialists and anti-imperialists.

The symbols they just kept while MLs had to find “new ones”.