The average user of Haskell, Rust, or ML today has certainly spent sufficient time in the Python/JS/Tcl/what have you mines.

The opposite is much less likely to be true; at best they may have done a project or two in Java or started migrating to TypeScript.

(Please also keep in mind: The average ML user probably reads, or intentionally avoids, HN. The average JS user doesn’t know it exists.)