Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.
So basically FlowType doesn't know about CSS Modules, a really handy way of dealing with the plagues of CSS in codebases (global variables and dependency wackiness mainly).
What WebPack allows us to do is "require" CSS files and use their class names:
import styles from "my_styles.css";
import React from "react";