Is it frowned upon to copy a whole web page but leave a link back? I have seen this countless times where a web site will copy an entire post but leave a link back to the original content. How does Google handle this as far as ranking? Also, I have seen some cases where the copied post has ranked higher than the original post. How can this be?
This is definitely
I would say this is frowned upon.
The legalities of doing things like this vary from site-to-site, it's usually outlined in their terms and conditions.
From a moral point of view, it's okay to quote specific parts of pages or articles or take small exerts, provided a link back accreditation is in place. Any instance where a publisher claims or implies ownership over content they've copied is both immoral and likely illegal.
The reason sites can copy articles and rank higher than the original is usually due to the overall domain authority or 'link juice' passed from other pages. It's also possible they built genuine links to their own page, making it seem more authoritative than the original source - possibly also causing Google to penalize the original source for duplicate content.
Thanks to updates like Panda and Penguin, these types are sites are being outed (from the SERPs, that is!) quicker and more often.
You can do your part by reporting instances of plagiarism or spam to Google.
Unfortunately this is more common since Google Penguin and Panda updates, despite claims to the contrary.
Most copies do not even link back, at least if this is done readers could easily find the original which in my case has the pictures and constantly updated content (which content is no longer "king" at Google, so updating content no longer helps in serps)
Google can easily tell the difference, and claiming authority is a poor excuse that Google trots out for the media to lap up.
Personally my aquatic sites are constantly plagiarized, as well my personal blogs and websites have had this happen. One clear example is an article listing Obama Failures that has many cited resources that has now fallen considerably behind articles that have pasted my article (including my grammar mistakes, which is like a signature for me to identify my articles)
Sadly there is little we can do, as Google no longer responds to DMCA complaints