Star Wars is a fiction but it is about letting the imagination go into different places.
For a lore explanation, the people of Naboo are a mid-rim culture, they have pretty developed and educated culture. They have developed an elective monarchy based on their own traditions. They decided that this works for them and Padme showed a great deal of leadership and ability; It makes sense when Anakin says: "They wanted to amend the constitution so you can run for another term of office".
It seems strange to us but that how Naboo does their thing.