[RussianCow]

This is clearly not true, since the DOM interface is implemented in something like C++ (or Rust, in this case) in browser engines, so you could write your logic in the same language, or even write a binding for any language you like.

[amaranth]

Last time I looked in to it this is true for at least Servo though. DOM objects use the SpiderMonkey GC for memory management since that makes them easier to work with from JS and means they didn't have to write a separate graph manager or GC. DOM hierarchy is worst case scenario for the Rust borrow checker, they don't work well together at all.