How does that make any sense? In the context of the timeline of the game (~3500BBY), it's important to have a lot of Jedi characters. Jedi in the Old Republic were plentiful; hell, Republic armies were usually headed up by the Jedi. Sith were also abundant; it wasn't until around 1000BBY that Darth Bane instituted the Rule of Two (i.e. one master, one apprentice).
A Star Wars MMO set in the Old Republic era can't work without playable Jedi.