Strictly speaking, casuistry is a case-based system of flexible moral reasoning which relies upon abstract methods in order to achieve an ‘optimal solution’ to a dilemma.
The video speaks to the very problem with this sort of arbitrary, human reasoning (as opposed to definite laws which are given by God) because no such human-derived solution exists, nor does life work this way. What usually happens in life is that we (the sinner) minimise and rearrange the facts of life to suit ourselves–thus the growing tattoo!
Historically, casuistry fell into great disfavor after Pascal criticised what he felt was the permissiveness of Jesuit casuistry and perhaps more than any other book, Luther’s ‘Bondage of the Will‘ uprooted the idea that the human will is autonomous or qualified to be a rational, moral guide…he also took issue with the practice of confession since he felt that it focused too much on the externals of sin and missed the spiritual component. (This was what I meant in the psychadelic kitty vid by the way–Jesus knew that appearances are always deceiving, the human is an iceberg with 90% of themselves submerged from view). Aristotle, on the other hand, was a proponent of casuistry and much of this sort of reasoning can be found/avoided in his Nicomachean Ethics.