You cannot be sure if your followers share the same idealogies and philosophy that you worship. One man can start a change but for its sustainability, followers are required. Those men and women, who can carry forward his baton and distribute in different directions, are essential so that the agenda could prosper everywhere at the same time. But coming to the original question; what if these followers become malicious. The leader can be great with his tolerance and endurance and other hefty values required to be one, but his herd do not reflect him and it should not. There is a difference between him and the group. He is there to lead them. Over the time, the original principles talked about by the leader can get some add-ons from the virus stricken minds of few followers who want to outsmart or take advantage of other naive followers. And unfortunately this is a fact with every ideology that persisted. Being it a religious one or political, all got inflicted with the later disciples that added their own wrong intents. The examples are omnipresent, Buddhism divided later into Hinayana and Mahayana based on Buddha’s incarnation theory. Sikhism divided into different beliefs under bogus religious saints in the modern situation. How come two persons claiming to follow Communist principles reckon a totally different actions on poor population? Lenin and Stalin had portrayed different drawings into the Russian canvas with the same brush of Communism.
Taking this theory further into technological advents. A person can invent a tool to help community thrive but the malicious users can use it for their own negative agendas. Being it any tool that constitue social media, the intent was to connect the world. But some political attention seekers have been using it to pollute the minds of the innocents by spreading rumours, to ultimately benefit a political party in an election. The recent Russian involvement in US Elections, is one of the many examples of such an action. Thus the followers can understand things limited to their capacity and such half knowlegdge or contexual one can give rise to apathy and hatred.