Why does an instance of Symbol respond_to? :dup

[addis_a]

Consider the following case:

define a symbol

name = :ευκλειδης

name.respond_to? :dup

true

name.dup

TypeError: can’t dup Symbol

Why leave in the public api of a class a method which shouldn’t be used?
Shouldn’t remove_method be called for :dup of Symbol?