Umbraco is a .NET project and as such you should work on it from within Visual Studio hence why the Visual Studio rules apply. Additionally if you are working with Umbraco in source control you are more than likely building addons for it which would also be wrote in .NET using Visual Studio,

The [VisualStudio gitignore](https://github.com/github/gitignore/blob/master/VisualStudio.gitignore) is not in the `Global\` folder so I don't see how it is a global ignore? I am suggesting that the user do exactly what you said, they should copy and paste the text from `VisualStudio.gitignore` in to their `.gitignore` before the text in this file. Without the VS ignores the Umbraco ignores are incomplete and I don't believe we should have the redundancies from `VisualStudio.gitignore` in this file.