Copy pasting for a sake of starting a discussion and adding your view is much different then the just copy paste image and put source link.
If forum allows this then their lot of user that just paste image/text and put source underneath. Mods always delete this post when reported.
Allowing these post will just flood bitcointalk from all kind of information from outside without any discussion happening in this forum.
But you will be always welcome to discuss the news/outside information if you really have to add something in it.
I agree, our local board is somehow half dead because of this kind of strategy, copy pasting, translating stuff that leaves a little room to a discussion. This kind of post does not stimulate readers to think and react since the sense of discussion is already killed there.
Its not plagiarism per se since the source is added.
I think this is subjective (
discussing about a starting thread post that copy paste the whole content and just leave a source link), bitcointalk is lenient with regards to plagiarism detection so this kind of action is not considered Plagiarism. But it is plagiarism outside Bitcointalk.
But factwise: it is plagiarism.
All of the following are considered plagiarism:
turning in someone else's work as your own
copying words or ideas from someone else without giving credit
failing to put a quotation in quotation marks
giving incorrect information about the source of a quotation
changing words but copying the sentence structure of a source without giving credit
copying so many words or ideas from a source that it makes up the majority of your work, whether you give credit or not (see our section on "fair use" rules)
from the source given by one of the reply :
https://www.plagiarism.org/article/what-is-plagiarism