The statement "Some leaders were tyrannical" does not evidence democracy in Sparta. However, evidence that Sparta had elements of democracy includes the role of the Assembly (Apella), where free male citizens could participate in decision-making regarding laws and policies, even though it was limited compared to modern democratic practices.
While Sparta was primarily an oligarchic system led by two kings and a council of elders (Gerousia), the Assembly did provide a platform for citizen participation, making it a unique blend of oligarchy and democratic elements.