The Systar System, as you can easily guess, consists of Bianca's LEGO bricks. What you might not guess, however, is that they're not the bad guys. When Bianca plays with Finn's minifigs, they're not brainwashed, but genuinely enjoying themselves more than they have in ages. It's particularly noteworthy that Batman, who's been characterized in this series as being both broodingly angry and reflexively opposed to any attempt to solve his deep personal issues, is not only convinced to enjoy himself, but to also fix his problem of being unable to hold committed relationships.
Lucy's the longest hold out, representing Finn's denial that enjoying anything not hard-edged can be okay, but even she ends up accepting the Systar denizens are not evil. Sadly, Bianca only played the Systar characters as "evil" and destructive because it was the only way to get Finn's attention. Who's the actual villain? It's Emmet.
More specifically, Emmet is at risk of becoming the villain. The reason Emmet and Rex Dangervest share the same voice? They're the same character. Rex is the "mature" version of Emmet from the future who's traveled back in time to guarantee Emmet will end up becoming him. The old Emmet might be naive, but he was also a genuinely kind and thoughtful person, whereas Rex might appear cooler, but in reality he's toxic masculinity personified. Emmet ultimately has to defeat Rex within Finn's subconscious in order for Finn to be a decent brother.
The LEGO Movie 2 isn't anti-darkness. The Apocalypseburg setting is genuinely fun, and even when Finn and Bianca reconcile, Finn's grittier creations can peacefully coexist alongside Bianca's sparkly poptimism, both seemingly incongruous sides influencing each other in fun and creative ways. What it is against is despair.
"Everything is awesome" is a childish sentiment that even the first movie, set entirely in the mind of a young child, could see was fake. "Everything is awful," however, is an adolescent sentiment that's ultimately even less helpful. What the film's thesis settles on, in a memorable musical number, is that everything isn't awesome, but that's no reason not to try to make things better.
That's an awfully useful message for both kids and adults. Far more sophisticated that the "edgy for the sake of edgy" mentality of, say, Zack Snyder's DC films (The LEGO Batman Movie already served as a worthy takedown of those). And this is all in the silly package of a LEGO movie.
Bill Maher, in all likelihood, is never going to watch it, nor will those comics fans with misplaced and overly defensive ideas about maturity. If either were willing to let their guard down and enjoy this gleefully silly children's movie, they might realize that maturity isn't about putting away "childish things," but about putting away the childish attitudes their reflexive rejections of being possibly perceived as childish ironically embody.
In theaters now, The LEGO Movie 2: The Second Part stars Chris Pratt, Elizabeth Banks, Nick Offerman, Will Arnett, Alison Brie, Charlie Day, Tiffany Haddish, Maya Rudolph and Stephanie Beatriz.