It simply wouldn't. To poison models that way, you need a huge amount of such subtly wrong code. Preparing intentionally bad code at sych scale is impractical.

It's easier to show clear garbage. That won't poison the model, but it gives them more work, and denies them access to good code, so they'll train on slop.

They're doing a good job of sabotaging themselves, they don't need our help - not more than simply not serving the crawlers.