Oof, I guess, you're not wrong that we've defined data races to be the separate issue of thread safety, but I am really not a fan of that separation.

IMHO you cannot cleanly solve thread safety without also extending that solution to the memory safety side.
Having only one accessor for a portion of memory should just be the n=1 case of having n accessors. It should not be the other way around, i.e. that multiple accessors are the special case. That just leads you to building two different solutions, and to thread safety being opt-in.

That's also the major issue I have with Java's solution.
If you know what you're doing, then it's no problem. But if you've got a junior hacking away, or you're not paying enough attention, or you just don't realize that a function call will take your parameter across thread boundaries, then you're fucked.
Well, unless you make everything immutable and always clone it, which is what we generally end up doing.