To place a barely-educated guess: because "... In Rust" is enough of a trope around here that it brings very specific crowds of people out to argue the same points each time, whether it's even remotely relevant to the link or not.

Better to just avoid it unless the "in rust" part is somehow intrinsically relevant (e.g. it's in rust for specific reasons that were previously too hard in other languages)

There is still brigading that happens regardless. I understand trying to minimize the battles but when there are actors propping up these same posts, it ends up having the opposite effect. (There are coordinated audiences on Discord and Mastodon looking to swarm these posts and game things like the front page of HN.)

Better to suppress these posts if the desire is to avoid the inevitable arguments with the bonus that it can be automated rather than requiring manual intervention. Otherwise, it likely ends up a well-intentioned but poisonous pill. I don't know if this will stop the most motivated members though.

Part "yes, you have a point" and part "this is letting perfect be the enemy of good".

There is apparently enough time and energy for manual intervention, given that it just happened - if it isn't making things worse, it may still be worth doing. Particularly since brigading tends to move in temporary bursts.

You would consider daily a temporary burst? ;)

It has abated quite significantly from its peaks, yes.

(I say as a user, which are the target of these actions, so I think it's pretty relevant that at least some feel that way)

Rust is well enough established at this point that titles don't need the extra juice.