I’ve asked this here before with no answer.
A search for 'Rosa Parks' turns up this previous answer by /u/PPP_Your_Boat:
[Why is Rosa Parks treated like the first person to defy the bus segregation laws when several people before her got arrested for the same thing?] (https://www.reddit.com/r/AskHistorians/comments/44kzfm/why_is_rosa_parks_treated_like_the_first_person/)