postgres: "alter default privileges" issue
Either you've forgot to add a permission to SELECT in the GRANT below, quoted from the question:

ALTER DEFAULT PRIVILEGES FOR USER access1
   IN SCHEMA access1 GRANT INSERT, UPDATE, DELETE ON TABLES TO access1_rw;


... or, if you really meant that having the role access1_rw doesn't let  read the tables even tough it lets write to them, then you must grant the role access1_ro to user1 (in addition to granting the role access1_rw).

Not having either of those has the consequence that user1 was never granted the right to SELECT from tables in the mentioned schema.