If doing this is such a bad idea then why is it so easy?

If doing:

  #define BEGIN {
  #define END }

were such a bad idea, then why is it so easy?

Maybe the language is poorly designed.

Or maybe the connection between being able to do something and it being a good idea to do something is just in your head.

In my experience, making obviously bad things difficult or impossible improves reliability. This idea certainly resides within my cranial cavity, but that doesn't necessarily make it wrong.

How could:

  HashMap = HashTable = Map = Table = Dictionary = Hash

possibly not qualify as "obviously bad"? The only reason you've offered up is because it is easy...

I think this is fine. The obviously bad part is being able to remove/change constants, especially as these changes are global.

The obviously bad part is that you pollute the global namespace for no reason other than laziness. When someone comes across code that uses a "Table" object interchangeably with "Dictionary" and "Hash", then he's going to have to look through the source code to find this bizarre line only to find out that you renamed a built-in container for no good reason.

Yes, I suppose that's also true.