You can talk the talk, but walking the walk is a different story. The OP was referring specifically to the latter - that Navalny indeed is one of the bravest, and that most people lose all their enthusiasm to object as soon as they or their loved ones are put a gun to their head (both literally and figuratively speaking). It's not cynical to observe and note this fact of life in an authoritarian state, it's simply being honest with themselves.