I'm also one of these people who doesn't "get the joke". This could be a mildly interesting example of a sort that doesn't need to do any comparisons, but it's

I'm also one of these people who doesn't "get the joke". This could be a mildly interesting example of a sort that doesn't need to do any comparisons, but it's certainly not "constant time" given that it needs to loop over all the input values (twice actually). In the end, this is basically just bucket sort, only that the buckets are managed by the OS. And nobody has ever claimed that bucket sort is constant time.