Anyways.. in an ideal world it would be great to see original posters being rewarded for their work, and is it always right to flag users that don't write their own content as per the examples I've given above? I think I read somewhere we should avoid flagging where possible.

I think if people are just cutting and pasting entire articles from other people without their permission or adding anything substantive, then that is a good reason to flag.

How you use the flag is quite subjective but I think most people agree on that.

You can also report such instances in the Steemcleaners:

https://steemit.chat/channel/steemcleaners-linkdrop