I personally became an anti-capitalist revolutionary before I became a Marxist. In fact, I was too busy in the '60s to read much Marx or Lenin; I only got around to reading them in the '70s after things had 'settled down' and I was girding myself for the long haul. I began calling myself a Marxist before I know a fucking thing about it; I merely noticed that for a century or so the major opponents of capitalism had been Marxists. That made me a Marxists; I became a revolutionary; then that caused me to become a Marxists; then becoming a Marxist caused me to finally get around to reading Marx and other Marxists carefully.
And that is just about how it has been with the greater proportion of communist revolutionaries for the last 100 plus years.
Carrol