How is code being "stolen" here? It's FOSS code that is being copied.

Take for example https://github.com/rust-stdx/stdx/tree/main/itoa. Its licenses and copyright information have been stripped. You are permitted to make copies of code under the MIT license, but the license also includes:

> The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

If the original repo were to disappear, it would be important to know who wrote the code and what the license actually is.