Those people existed before the Internet was widely available. They just shared information via books, leaflets etc. Arguably I'd say the Internet makes it less

Those people existed before the Internet was widely available. They just shared information via books, leaflets etc. Arguably I'd say the Internet makes it less sustainable as they can't help but be exposed to contradictory beliefs. However it also makes it easier for them to organize and spread their ideas... I'd love to see data on wether this is a net gain/negative.