real-life
Explanation
The Joke
A student is complaining about not wanting to do homework, and an older person (likely a parent or teacher) tells them "You don't wanna do homework? You wait until you get to real life." The student asks if real life is harder, and the adult responds that real life is actually way easier -- it's just that "almost nobody will care whether you do your work or not."
The adult then goes further, explaining that formal school is actually the last place in the student's life where someone will genuinely care about whether they have an opinion on a topic and how they express it in words. The punchline comes when the student asks "Now then, who wants a slanted reading list?" and the adult responds "Honestly, still no." The comic subverts the typical "real life is harder" lecture by arguing that school is actually the harder, more demanding environment because people are actively invested in your intellectual development.
The Humor
The humor works on multiple levels. First, there is the reversal of the common adult threat that "the real world is harder than school." Instead of the expected warning, the adult delivers a more cynical but arguably truthful observation: nobody in the real world will care enough to push you the way teachers do. Second, the final panel adds another twist -- even after this rousing defense of education, neither person actually wants to engage with the difficult intellectual work (the "slanted reading list"), undermining the very argument just made. It is a characteristically SMBC move: setting up a philosophical point and then immediately puncturing it with human laziness.