You two seem to have figured this out, but as far as I can tell, the disconnect here is that the vast majority of security issues related to the separation difference between VMs and containers isn't due to container "escapes" at all. It's due to the defaults of the application you're running assuming it's the only software on the system and it can run with any and all privileges. Lazy developers don't give you containers that work without running as privileged and demand from users to use that application after migrating from a primarily VM-based IT infrastructure to a primarily container-based one is too great to simply tell them no, and if it's free software, you have no ability to tell the developers to do anything differently.

Discussions on Hacker News understandably lean toward the concerns of application developers and especially greenfield projects run by startups who can take complete control of the full stack if they want to. But running applications using resources partially shared by other applications encompasses a hell of a lot of other scenarios. Think some bank or military department that has to self-host ADP, Rocket Chat, a Git server, M365, and whatever other hundreds of company-wide collaboration tooling the employees need. Do you do it on VMs or containers? If the application in question inherently assumes it is running on its own server as root, the answer to that question doesn't really depend on kernel CVEs potentially allowing for container escapes.

If we're just reasoning from first principles, applications in containers on the same host OS share more of a common attack surface than applications in VMs on the same physical host, and those share more than applications running on separate servers in the same rack, which in turn share more than servers in separate racks, which in turn share more than servers in separate data centers. The potential layers of separation can be nearly endless, but there is a natural hierachy on which containers will always sit below VMs, regardless of the kernel providing the containers.

Even putting that aside, if we're going to frame a choice here, these are not exactly kernels on equal footing. A kernel written in C that has existed for nearly four decades and is used on probably trillions of devices by everything from hobbyists to militaries to Fortune 50 companies to hospitals to physics labs is very likely to be safer on any realistic scale compared to a kernel written in Rust by one college student in his spare time that is tested on Qemu. The developer himself tells you don't use this in production.

I think the annoyance here is it often feels when reading Hacker News that a lot of users treat static typing and borrow checking like it's magic and automatically guarantees a security advantage. Imagine we lived in the Marvel Multiverse and vibranium was real. It might provide a substrate with which it is possible to create stronger structures than real metals, but does that mean you'd rather fly in an aircraft constructed by Riri Williams when she is 17 that she built in her parents' garage or would you rather trust Boeing and whatever plain-ass alloy with all its physical flaws they put into a 747? Maybe it's a bad analogy because vibranium pretty much is magic but there is no magic in the real world.