I'm sure he's at least mostly right about the cheating thing, because in many cases the Linux-compatible EAC binary is just a stub with literally no detections of any kind. And even if they did have detections, given that the EAC runs within Wine they'd have no way of detecting something as simple as information cheats (wallhacks, ESP) that read /proc/$(pidof rust.exe)/maps from Linux userspace. For a game like Rust, such cheats are probably the most popular ones.

What I do seriously doubt is his claim of Linux users making up "less than .01% of the total player base". It just seems incongruent with the total Linux user market share on Steam. Though he does qualify it by saying this stat is from when they stopped supporting Linux, i.e. 2019. The situation is obviously quite different now with Linux being at 3% total and ~6% of English-language users on Steam, so if it's not an outright lie it's at least very disingenuous.