Further evidence that the rating system is bullshit.

This argument really only holds water if the purpose of film and television ratings were to make commentaries on social moral trends.

Unfortunately they have an explicit and expressed purpose that is not that. They are a tool which is intended to inform and guide consumers on the content of a product ahead of purchase so they can make an informed decision. They should be locked to a standard which does not change, or all previous ratings should be reevaluated when the standard is changed. The media does not go away. And all ratings should be directly comparable, regardless of: when they were rated, who the "intended" audiences are, or what genres they belong to.

As a slightly hyperbolic example (pardon the minor straw man), imagine you are a Christo-Facist who, among other things, believes that nudity is a sin and you never want your children exposed to the evils of a bare breast. So you set your TV to only show G or PG movies. Then you find your child watching the 1984 rom-com Splash and boom, tiddies in a fish tank. It is PG because the PG standard allows for brief nudity (https://www.filmratings.com/).

They don't apply the standards they have. They routinely make decisions based on backlash from Christo-Facist "Parent's" groups which means that film ratings increasingly do not reflect the overall moralistic stance of the greater society.