"If these benchmarks were run on idiomatic Objective-C"

    s/idiomatic/pure/

I haven't programmed it much, but to me, idiomatic objective-C is when you use it as a sort-of scripting layer on top of your C code. No sane programmer would write ten layers of Objective-C message passing code; two or three is fine, on the bottom of your call stack (and hence, rarely executed)