COM is not obsolete at all, it's the main way Windows APIs have been and are provided from the release of DirectX until now, where it underlies the current WinRT API.
The writer is the person who added VBA to Excel + the MS Office suite. Where you used COM to make use of external libraries/programs. I assure you, he's not ignorant.
Is COM obsolete today? For new development, yes. But Microsoft still supports it and you can still write .net code that gets exposed as COM objects.
Indeed. COM provided and provides integration that Unix nerds can only dream of. Windows in the 90s, in general, was technology indistinguishable from magic, compared to the state of the art from the Unix realm. That's why it would have killed Unix entirely but for Linux.
Is COM obsolete today? For new development, yes. But Microsoft still supports it and you can still write .net code that gets exposed as COM objects.