I cant speak for that guy but my take is that all of the strings except rarrr should statically defined in the object that defines their behaviour. They may even be integers instead of strings to speed things up. Then you would need some way to avoid collision for the event integers shared across many objects.

Repeating strings is hard to refactor and comparing strings is much less efficient than comparing integers. Think about making sure every bit in two 2 * 8 * length string of bits plus overhead is the same vs two 32bit integers. The latter far fewer cycles.