You're conflating two things. The fact that he voices his belief that Rust is harmful for kernel development is fair.
The fact that he is using his powers as maintainer of the DMA module to prevent Rust code from being added, with the explicit goal of making it harder to develop Rust drivers so that maybe the Rust-for-Linux project might get abandoned is an explicit act of sabotage against the R4L project (no one is saying he is sabotaging the Linux project itself).
In contrast, even accepting the "two languages bad" perspective, you can't call the R4L project "sabotage" in the same way, because they are clearly not intending to prevent or break anything in the Linux kernel, even if you think they will end up doing so as this maintainer does.
>The fact that he is using his powers as maintainer of the DMA module to prevent Rust code from being added
This is a misinterpretation of the facts. It's not actually up to Hellwig whether or not the patch gets accepted; the relevant maintainer that would merge the patch is somebody else.
He's totally within his right to express his opinion in a NACK.
At least at some point, the proposal was to add this code in the DMA submodule, where he did have the ~final say whether it would be merged in.
When it became clear that wasn't an option, they decided to put it somewhere else, but since he'd been consulted, he still wanted to make it clear he isn't ok with the patch regardless of where the files go or any other aspect of it; but you're right that he is not the final authority on what code goes into that new subpath.
I never said in any way that he doesn't have a right to his opinion. Just that he is explicitly and vehemently opposed to Rust in the kernel, and to anything that makes that easier to happen.
The fact that he is using his powers as maintainer of the DMA module to prevent Rust code from being added, with the explicit goal of making it harder to develop Rust drivers so that maybe the Rust-for-Linux project might get abandoned is an explicit act of sabotage against the R4L project (no one is saying he is sabotaging the Linux project itself).
In contrast, even accepting the "two languages bad" perspective, you can't call the R4L project "sabotage" in the same way, because they are clearly not intending to prevent or break anything in the Linux kernel, even if you think they will end up doing so as this maintainer does.