I'm thinking of making a copy of all my country's open data portal datasets. I will be rate limiting my downloads. Is that okay or is it bad manners to get a full data dump? I am asking of the ethical/moral considerations.
Bad manners have nothing to do with it. As a taxpayer, it's your data, and they're making it available for you to download. Your country also benefits from having backups of their dataset floating around out there.
You could take the public service angle of it to the next level by uploading a copy of the full archive to the Internet Archive using their S3-compatible interface: https://archive.org/help/abouts3.txt
If you think their system is creaky and might strain at giving you the full dataset, or you think there's a more efficient way for them to give you a full dump -- then you can always email or call and ask them.
But do it after you've got your first complete copy downloaded, just in case.
The Philippine Government has published (Jan. 2014) on the government website (gov.ph) the 2014-2106 action plan for open data. In Section 8, Appendix F (Creative Commons Attribution 3.0 Philippines) describes how the data is licensed to the public. From my reading of it, you are free to create derivative works (e.g., your own archive), including for commercial purposes - but most provide attribution back to data.gov.ph.