I'm generally not a fan of the way people go about D&I, but the fact JeanHeyd has brought up the problem before makes it more pertinent.

Whoever on the Rust team made the decision to reach out and downgrade JeanHeyd's talk seems extremely incompetent.

Optics matter a lot here and a large portion of leadership roles is optics. It's careless to not take context into account, like the recent history of poor Rust-related optics (E.g. trademark thing) and JeanHeyd (The person they invited) talking about lack of black representation.