This is just plainly not true. Mozilla is one part of Rust's governance, but is nowhere near a controlling stake. We deliberately designed it so that control by a singular organization is impossible.
Participation is not control. Mozilla cannot make decisions about Rust’s future. They can participate in the open process to make those decisions, but we operate on consensus, and they’re a small minority of the stakeholders.
I’d object to “shilling”, but I still advocate for Rust. Mozilla plays no part in my decision to do so, for better or for worse, for exactly that reason: they’re not in control of it, so I’m not sure why that’s relevant.