Science fiction allows us to explore the ramifications of theoretical political systems in a way that is not possible in reality except over very long timescales and with extremely cooperative citizens.
A lot of sci-fi instead seems to recontextualize common human issues into an environment where existing political pre-conceptions can be avoided. Obvious examples are things like the half black/half white episode[1] of Star Trek TOS or "Measure of a Man"[2] from Star Trek TNG. These are pretty highly regarded episodes and neither really has anything to do with the Federation of Planets or its political system (in fact there are very few episodes that deal with these topics). Instead they're explorations of racism and what it means to be human/sentient.
[1] https://en.wikipedia.org/wiki/Let_That_Be_Your_Last_Battlefi...
[2] https://en.wikipedia.org/wiki/The_Measure_of_a_Man_(Star_Tre...