You complained about them salting using the public username as salt. You asserted that this makes the rainbow table computable offline. I asserted that this did

You complained about them salting using the public username as salt. You asserted that this makes the rainbow table computable offline. I asserted that this didn't matter much for security since the table for H(username || secret) is username specific and not reusable for other usernames. Since precomputed rainbow tables consume quite a bit of space it is rather unlikely that anyone would have such a table stored for any random username.