In my experience with multi-threaded programming, C++ code with "careless sharing issues" is often filled with multiple threads accessing the same object and relying on convention to avoid calling the wrong thread's methods, pervasive data races and unsynchronized variable access, mistaken use of mutexes on only one side of shared memory, and logical race conditions that require adding mutexes (risking deadlock) or rewriting code to address. Whereas Rust code tends to not have these issues to begin with (outside of the implementation of synchronization primitives), store reader and writer methods on separate handle objects, use Arc to manage cross-thread shared memory, and similar which makes the code either correct or tractable to learn and make correct.

I also struggle to understand the threading model of COM and C libraries like libusb (https://libusb.sourceforge.io/api-1.0/libusb_mtasync.html), though that might just be me, and each library tends to have a different threading model. Rust's Send/Sync is a 90% solution which you can learn upfront, is checked by the compiler, and applies to all libraries and works for most use cases.