Unity, why fail a build if the build directory isn’t empty?

When building a project using Unity 2020 LTS (probably 2019 as well), if you build a Mono project inside a directory that has a IL2CPP build of the same or different project, you’ll get an error saying that you shouldn’t build a Mono/IL2CPP project inside a existing Mono/IL2CPP build directory. And that fails the entire build.

How hard is it to just ask the user via a prompt if they want that folder cleaned up before copying the built files to the destination, rather than failing a 10-minute build cycle?

Sigh. Guess I’ll go manually clean the output directory up myself.