Low quality, bug laden code has existed long before LLMs and it'll continue to exist long after. Their rationale about avoiding future headaches could literally apply to any open source project they have a dependency on.

There is quite the selection bias going on here... you aren't hearing about the successful projects.

Doesn’t bun have a massive test suite that the rewrite passes? What else do people want?

Vibe coding from scratch is far from translating an existing app to another language.

I don't know any bad stories about ai-translated apps. Partially because it's a relatively new trend, but also because a big amount of usual vibe code fail modes are not applicable here.