Bernard Shaw said this in 1907 (when there was much admiration around for Nietzsche’s Superman idea):

” Beware of the pursuit of the Superhuman: it leads to an indiscriminate contempt for the Human. To a man, horses and dogs and cats are mere species, outside the moral world. Well, to the Superman, men and women are a mere species too, and also outside the moral world”.

[Don Juan in Hell]

See under Writings