like allowing differences of opinion and anti-authoritarianism

Getting steamrolled by nazis after inviting them to the table under pompous pretenses of "allowing differences of opinion" isn't even a viable starter for a government. The Weimar Republic comes to mind.

The in-setting excuse for why the Federation survived at all, shaky as it was, is that it employs cryptofascists already and gives them unchecked privileges to surveil, harm, and murder on a whim to maintain the status quo: Section 31. You might be a fan.