Celeste, FFXIV, Coffee Talk, The Last of Us, Life is Strange, Night in the Woods, it's good time for gaymes. We're all being pumped full of propagaynda and it the world is better for it.
Undertale isn't a masterpiece. The moral of the game is that children who are beaten shouldn't fight back. The mother figure everyone fawns over is an abuser who beats up a child for trying to leave her. The game is only popular because its target audience are adults who were abused as kids and want an excuse to slip back into that mindset and be told their trauma reactions are justified.