How do I load a data-only dump created with pg_dump to another database?
If you are happy with recreating the tables upon restore (and I see no reason why one should not be happy :), then you could use the --clean option:


  -c
  --clean
  
  Output commands to clean (drop) database objects prior to outputting the commands for creating them. (Unless --if-exists is
  also specified, restore might generate some harmless error messages,
  if any objects were not present in the destination database.)
  
  This option is only meaningful for the plain-text format. For the archive formats, you can specify the option when you call
  pg_restore.


Use it with pg_dump when creating plaintext dumps, or with pg_restore when using any other format.  In both cases, you will need a full dump, as a data-only one would lack the information for creating the tables.

Note: don't use INSERT statements in your dumps (--inserts does this in pg_dump).  It is almost invariably slower than relying on the default COPY functionality.