Define "decent".
Good question. You (or I) have opened a can of worms.
Decent, at minimum, might mean: No implied, desired, suggested, actual or tolerated violation of the 6th or 9th commandments. No misrepresentation or denigration of marriage. No suggestive or overly sensual clothing or behavior. No blasphemy or profanity.
Wow. That cuts out allot of movies.
I say that a movie with just one scene of fornication, etc. is riddled with countless other subtle assumptions and "givens" that are far from reality and God's truth.
Sure seems to be the case. But why would a Catholic family be watching such a movie to begin with ?
And I submit that such subtle brainwashing, behavior, and "digs" at Catholic culture are much more nefarious and damaging than any flesh or blood (sex or violence) on the screen -- those things are easy to catch and avoid.
Even movies that act as though the Christian perspective never existed are dangerous.
Yes, I concede that there are very few movies that could be patched up to 100% edifying condition.