Yeah, of course: if you are the kind of company that like a having tens of thousands of engineers working on five different versions of the same thing, with one team explicitly working on solving a problem another team has but without helping them as that's some combination of not-fun and not-promotion-worthy, you can of course do whatever you want.

Or they have context that helped them decide to do something this way?

lol, sure.

Some obvious context from an outsider:

1. It's designed to run on Fuschia, not Linux

2. Go FFI is very inefficient, you can't just "extend" a Go project with native bindings and get the same performance wins

3. Hopefully the gvisor team learned the obvious lesson that Go is not suitable for this kind of work