Marxism killed far more people in far less time, than Islam. Karl Marx was a satinist. Marxism is straight up satinism. And everything that Lenin did was already written by Marx. “ Swept out of the way” means extermination.
Communism perhaps killed more people than Islam. Communism had the advantage of coming to maximum power during a time of the most people around to get killed. Islam was mostly defeated until all that oil that its infected members were sitting on breathed new life into it. Islam definitely has had more staying power than Communism.