Honestly, this seems like he's being serious because it falls inline with the subversive nihilism and degeneracy of Rick & Morty generally.

Everything is degenerate, everything is disgusting, there are never standards to any behavior, there is no integrity, nothing makes sense, nothing has value, and you're just a worthless spec bound to die.

There's a huge problem with pathological nihilism being directed at kids and teens, and they are unfortunately especially susceptible to it.