CREATE POLICY bug ?

CREATE TABLE public.policy_tab

(

  id bigint NOT NULL,

  description character varying(160) NOT NULL,

  usr name NOT NULL,

  CONSTRAINT policy_tab_pk PRIMARY KEY (id)

);

ALTER TABLE public.policy_tab OWNER TO postgres;

GRANT ALL ON TABLE public.policy_tab TO public;

CREATE OR REPLACE VIEW public.policy_view AS 

 SELECT id,

    description,

    usr

   FROM public.policy_tab;

ALTER TABLE public.policy_view

  OWNER TO postgres;

GRANT ALL ON TABLE public.policy_view TO public;

ALTER TABLE public.policy_tab ENABLE ROW LEVEL SECURITY;

CREATE POLICY standard ON public.policy_tab

    FOR ALL

    TO PUBLIC

    USING (usr = current_user);

INSERT INTO public.policy_tab (id, description, usr) VALUES (1,'uno','manager@scuola247.it');

INSERT INTO public.policy_tab (id, description, usr) VALUES (2,'due','manager@scuola247.it');

INSERT INTO public.policy_tab (id, description, usr) VALUES (3,'tre','manager@scuola247.it');

INSERT INTO public.policy_tab (id, description, usr) VALUES (4,'quattro','teacher@scuola247.it');

INSERT INTO public.policy_tab (id, description, usr) VALUES (5,'cinque','teacher@scuola247.it');

and the the oupt was what i excpected:

rows 1,2,3 for user: manager@scuola247.it

rows 4,5 for user: teacher@scuola247.it

rows 1,2,3,4,5  for user:  postgres (the policy doesn't work for him)

but when i run the query: "select * from public.policy_view"

the ouput is the same (all rows)  for all users 

i'm doing some mistakes or this is a bug ?

thank you in advance for the time you would like dedicate to me.

Andrea Adami