Why can't we have the same anti-spam feature that WoW has?

[Sacred-Oblivion]

They also made it where they were it was required to be level 10 on their character to whisper.

I know that this statement is false for during the time I played. I can't say if WoW has this implemented now, but if it does then they did it for another reason because stopping low lvl chars from whispering wasn't necessary to stop RMT spam during the time I played.