...Which is great if you think that everyone has a valid perspective to contribute—and they do! ...They absolutely do not. 90% of the work of a political theorist teaching in an introductory setting is correcting misreadings; if I had a nickel for every time I had to explain (to otherwise very intelligent students) that Machiavelli does not teach 'the ends justify the means' I would be a rich, rich man. There are bad readings and understandings of any cultural work, and these deserve neither time nor platform nor respect. They are worse on average than professional or academic critical work, because that professional status means (usually) a considerable amount of time given over to careful reading and attention which the average consumer of culture is unable to match.
What amateur forms of criticism are is easier: looser and more inexact in their standards, more willing to indulge desires rather than consider the merits of serious work (/more likely to be confused about what makes something 'serious'), less able to place narratives and tropes in their cultural and historical context. Consider: political theorists like to make fun of philosophers for the fact that contemporary philosophy rarely engages with anything older than John Rawls, which is to say they only consider work done since 1971. The average cultural frame of reference for, say, the average comic book movie extends no further than, at best, the first X-Men movie, and in no event to any sort of film at all prior to 1980 (Star Wars is the touchstone, and that's only 1977). Thus criticism, if it can even be called that, which is a thousand miles wide and an inch deep. Rigor is the price of accessibility, and accessibility really only makes it easier to accept the mediocre and think it's amazing.