[olavk]

It has an "encyclopedic tone" but that does not mean it is objectively correct or makes a sensible argument. It is not the number itself that is illegal. What would that even mean? Humans doing certain things with certain intentions can be illegal.

The article links to "illegal numbers", which weasely states "if communicating a specific set of information is illegal in some way, then the number may be illegal as well". Note the "may", and the only references seem to be pure speculation.

Some people argue any kind of copyright and IP rights should be abolished, but who would argue it should be completely legal to phone in a bomb threat because "it is really just a number represented as sound"?