Thank you for the opportunity to help you with your question!
Vesey was a slave who won his freedom out of blind luck . He won a lottery and was able to buy his freedom but was unable to do the same for his wife. The fact that he was a former slave who had gained his freedom but wasnt quick to forget his past and move on and still risked all he had for the cause of freedom was what aspired other to view him as a leader. Also the fact that he was a religious figure (priest) also played a significant part as most of his followers where members of his congregation
Please let me know if you need any clarification. I'm always happy to answer your questions.