There are only two reasons to learn something. Either because you need it or because you love it.
The content you need to know is fairly focused. From the traditional curricula, what you need to know is mostly centered in a few classic school areas such as reading, writing, and arithmetic. What you need to know should also be expanded as well to include areas not covered in traditional curricula, such as stewardship, project management, innovation, and security. This content is fairly consistent across populations.
And then there are the things that we love. Here, learning is nearly automatic. What we love is highly individualistic. For some, this might include music. For others, it may be trucks. Or clothes. Or movies. In this age of the Internet, the rigorous pursuit of our passions (sometimes life long, sometimes extinguished before the first YouTube video is done) is infinitely possible and exposes us to a naturally broad spectrum of curricula, that should even draw the "need to know" skills.
This begs the question, what are insufficient reasons, even bad reasons, for feeling obligated to learn something?
One bad reason is, "because everyone else is doing it." The existance of a curricula, or the common use of it, is not sufficient reason for anyone to use it. Likewise, students should not learn something just because it is a requirement for a subsequent grade level.
Second, "broad early exposure" is not a reason to learn anything. Schools and parents, so afraid that neuron synapses will degrade in infants, have felt increasingly justified in exposing children to everything from foreign languages to curry. Life is filled with infinite varieties of stimulation. Rich exposure to the real world is better than an artificial list of "critical early childhood stimulation," especially when administered through sterile media.
Finally, "cultural literacy" is a bad reason to know anything. This includes Shakespeare. There was an argument made most famously in Hirsch's work that there are themes that every person should know in order to communicate efficiently with their world. While this may be true, for old people to attempt to freeze a body of knowledge, such as scientists used to do by giving everything a dead language (Latin or Greek) name, is unnatural. We are all "of our time" and references flow naturally, be they from Milton or Seinfeld or Twitter. Common references are the output of a diverse life, not just an input to it.