To be fair, that's not always been the case. Last time I tried the profiler under OS X, it all seemed to work, but the actual figures produced by the profiler were nonsense. Other platforms seemed unaffected. That was quite a while ago. If they've fixed it, then great.
EDIT: It seems a kernel patch is required to get it to work correctly on the Mac: http://godoc.org/rsc.io/pprof_mac_fix