How does the song "Sign of The Times" by Harry Styles relate to the theme of isolation in The Chrysalids?

From the very beginning of this story, readers can see that the Waknuk society is a very isolated society. This isolation theme comes in a few formats. One of those formats is that the Waknuk society actively tries to isolate its gene pool from any changes. Anybody that has a trait that isn't considered "normal" is labeled a "Deviant." These people are either killed, expelled to the Fringes, or sterilized. In each case, passing on that particular set of genetic coding to future Waknuks is impossible. It's a very genetically isolated community. David knows that he is a Deviant, and this forces himself and others like him to isolate themselves as much as possible from the community. They have to hide their gift. As the story continues, David and his friends are forced to flee. They are trying to get help from the Sealand woman. This eventually happens, and they are taken to a great city. On the way there, the Sealand woman tells David that the Waknuks are an inferior species that is slowly going extinct.

"Your minds are confused by your ties and your upbringing: you are still half-thinking of them as the same kind as yourselves. That is why you are shocked. And that is why they have you at a disadvantage, for they are not confused. They are alert, corporately aware of danger to their species. They can see quite well that if it is to survive they have not only to preserve it from deterioration, but they must protect it from the even more serious threat of the superior variant.
For ours is a superior variant, and we are only just beginning."

The Sealand woman isn't sad about any of this. She explains that it is simply a sign of the times. The Waknuk's aversion to genetic change through isolation likely was a large contributor to its eventual downfall. The Harry Styles song echoes this part of the story. Just like the Sealand woman tells David that he has to get out of that isolated and dying society, the song speaks of the same concept of needing to leave a broken part of your life.

Just stop your cryingIt's a sign of the timesWe gotta get away from hereWe gotta get away from hereStop your cryingBaby, it will be alrightThey told me that the end is nearWe gotta get away from here