It is a hack. The article lists a whole series of things that are standard in other languages that you can't do in go. Here are some examples:

  Find smallest/largest element in slice
  Find average/standard deviation of slice
  Compute union/intersection of maps
  Find shortest path in node/edge graph
  Apply transformation function to slice/map, returning new slice/map

And here are data structures that other languages have but go does not:

  Sets
  Self-balancing trees, with efficient insertion and traversal in sorted order
  Multimaps, with multiple instances of a key
  Concurrent hash maps, supporting parallel insertions and lookups with no single lock

If it were not a hack, then go would not have these limitations.