It sounds like its BASED on the same IDE, but fundamentally provides a completely different feature set, and ability to compile to completely different platforms. That's fundamental enough to suggest its not the same IDE.

If anything, MS is simply capitalizing on the brand recognition, and taking a similar approach. But if the extensions don't work on Mac - its not the same.

That's like saying "Microsoft Word, the same word processor you love, on a mac" and then not support .docx files.