While your objection to the use is clear, and while my sympathies lie squarely with any objection to the weakening or dilution of dystopia's force, any novel or movie that pertains in any way to 'dystopia', may legitimately be described as 'dystopian'--however little we may like that use of the term.
'Dystopia' was apparently formulated on the model of, and in contrast to, More's post-classical Latin term, Utopia. The earliest use I could find of 'dystopia' was this from a poem titled "Utopia", published in 1748:
(From The Gentleman's Magazine, Volume 18, John Nichols, F. Jeffries, 1748.)
The poem quoted, being satirical, does not mistake the sense of Utopia, and uses 'Dystopia' in a similar way, as the name of a 'no place' with bad qualities in contrast to the good qualities manifest in Utopia (according to the narrator of that work).
Utopia did not mean, however, an ideal, imaginary place having "a perfect social, legal, and political system". Such is how the unreliable narrator of More's satirical De optimo reipublicae statu, deque nova insula Utopia (1516) presents Utopia, yet the meaning of Utopia was 'no place' or 'nowhere'. Utopia does not and did not exist.
By the 1800s, however, 'utopia' had taken on a new meaning, partly by conflation with 'eutopia' as the opposite of 'dystopia':
b. A real place which is perceived or imagined as perfect.
["utopia, n.". OED Online. December 2015. Oxford University Press. http://www.oed.com/view/Entry/220784 (accessed December 31, 2015).]
This sense is attested with quotes dated from 1828 to 2010.
In contemporary use, 'dystopia' conveys the opposite of the contemporary positive sense of Utopia. It draws this opposition in part from the long-standing conflation of 'utopia' and 'eutopia': 'dys-', meaning 'bad', is opposite 'eu-', meaning 'good'. Thus, 'dystopia' may be understood as 'bad place', 'eutopia' as 'good place', and 'utopia' as 'no place' but also as 'good place' by a largely mistaken association with 'eutopia'.
The circumstances described in the preceding paragraphs weaken any argument that might be made against the casual use of 'dystopia' (and so 'dystopian') to describe a possible place, state or condition, however imaginary that place might be. That weakening is aggravated by 'eutopia' having, historically, been used with the sense of a possible place:
A perfect (imagined or hypothetical) society or state of existence; a place of supreme happiness. Also: a literary work describing such a place; a vision of an ideal state of existence. Cf. utopia n.
In early use sometimes distinguished from utopia in being a possible, rather than purely imaginary, place of happiness (see e.g. quots. 1556, 1610). Now chiefly used synonymously with utopia, though sometimes used to emphasize the positive nature of the imagined state or society, with reference to the sense of the ancient Greek prefix....
["eutopia, n.". OED Online. December 2015. Oxford University Press. http://www.oed.com/view/Entry/65148 (accessed December 31, 2015).]
Setting aside, then, any quibbles about how all novels and movies necessarily represent imaginary places, states and conditions (however much those imaginary places, etc. are based on "truth"), and thus are appropriately described with terms suited to describing only imaginary places etc., the historical and contemporary use of both 'dystopia' and 'utopia' encompasses meanings that include possible or real places, states and conditions.