How can people say Ice is the worst type when Psychic exists?

>Weak to Knock Off, Sucker Punch and Pursuit
>Weak to more types than it can hit super effectively
>Literally no reason to use for beating Fighting because Fairy does it much better
>Earthquakes incredible distribution, high power and accuracy makes it better for dealing with Poison types

Ice Pokémon may not be good, but at least many non-Ice types can benefit from carrying an Ice attack. There's never a good reason to put Psychic or Psyshock on a non-Psychic type.