That seems like it could be an issue, but not the issue being raised by the post. The original post was talking about executing binary code on a user's machine without consent. The thing is, this is how a lot of Rust packages work. Any package can have a build.rs that runs arbitrary code on a developer's machine (that gets compiled into a binary automatically by Cargo). Any proc macro is arbitrary code that gets compiled into a binary and executed on a developer's machine. In fact, any library, regardless of if there's a build.rs or if it's a proc macro, can have malicious code in it that gets executed when a developer calls a specific method.

None of this is new. When done maliciously, it's called a supply-chain attack. All packages can do this. This is part of why there's been interest in executing some of this code in WASM runtimes within the compiler, so that developers can explicitly control the level of impact those packages can have on a developer's machine. That being said, WASM doesn't solve the fact that any package can just have malicious code in it that gets executed during runtime. This is why people should vet their packages themselves (when it's important, at least) to ensure that this won't happen to them.