pg_dump_remove_comments.log

$ createdb test_input
$ psql test_input -c "CREATE TABLE strs(s text); INSERT INTO strs(s) VALUES('-- hi');"
INSERT 0 1
$ createdb test_output
$ pg_dump test_input | sed -e '/^--/d' | psql test_output
SET
SET
SET
SET
SET
 set_config 
------------
 
(1 row)

SET
SET
SET
SET
SET
SET
CREATE TABLE
ALTER TABLE
COPY 0
$ psql test_input -c "TABLE strs"
   s   
-------
 -- hi
(1 row)

$ psql test_output -c "TABLE strs"
 s 
---
(0 rows)

$ psql --version
psql (PostgreSQL) 12.8 (Ubuntu 12.8-1.pgdg20.04+1)