This article reads a lot more like "In praise of Cocoa" than anything specific to Objective-C, the language. The author clearly sees them as one beast when they are quite separate. It's somewhat reasonable to lump them together since developing anything in Objective-C without Cocoa is generally prohibitively difficult given the lack of other library support.

That said, nothing he's really talking about has to do with the language itself (save, perhaps, for the performance characteristics closer to C++ than Java). He's more praising what C# developers always praise: he's basically describing it as "Java done better than Java."