People keep saying this but it's obviously not the same thing.

Very, very few drivers drive as "erratically" as the cyclists the OP is concerned about. People also don't tend to drive cars amid other much-slower (and smaller) traffic. (They really wouldn't be able to (for very long).)

What is going on is more like what you often see with motorcyclists in stop-and-go traffic or on highways with low traffic (where smaller/faster motorcyclists can weave through other traffic). It's a very similar dynamic. Car drivers also have the same basic response to motorcyclists riding in those ways as "real" cyclists have with to sidewalk cyclists.

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Anyway, it's nice to have one activity that does involve licensing!