Nah, that is not it. If it happens at all, it's very rare that any person starting a thread doesn't know how to archive a page to avoid giving traffic to undeserving websites. Also, since I always search for the source when a link is not provided, I know that, most times, the screenshot used is from a conservative website and the OP would have had no reason to avoid giving traffic to it. Look at this thread here, for example, someone else found many sources that, even if not archived, could have been linked to without a problem, There is really no valid reason why an OP wouldn't provide a link to the source.
The only thing I can think of is that, since OPs want people to upvote and comment so their thread ends up on "HOT", they might think that, if people leave the thread to read the source article, they won't come back to the thread to upvote and comment, so they don't offer a link. I know that this sounds like a petty and stupid reason, but there is literally nothing less petty and stupid that can explain why an OP would take and upload a screenshot of a headline, or copy/paste an excerpt of an article, and not add a link to the source.
I think they don't want to link to certain sources they don't want to give traffic to. Archive links are great!
Nah, that is not it. If it happens at all, it's very rare that any person starting a thread doesn't know how to archive a page to avoid giving traffic to undeserving websites. Also, since I always search for the source when a link is not provided, I know that, most times, the screenshot used is from a conservative website and the OP would have had no reason to avoid giving traffic to it. Look at this thread here, for example, someone else found many sources that, even if not archived, could have been linked to without a problem, There is really no valid reason why an OP wouldn't provide a link to the source.
The only thing I can think of is that, since OPs want people to upvote and comment so their thread ends up on "HOT", they might think that, if people leave the thread to read the source article, they won't come back to the thread to upvote and comment, so they don't offer a link. I know that this sounds like a petty and stupid reason, but there is literally nothing less petty and stupid that can explain why an OP would take and upload a screenshot of a headline, or copy/paste an excerpt of an article, and not add a link to the source.