The first line clearly states that the words that come after the : will be a quote.
Then, he should provide a link to the source AND
- use quotation marks
That would be the ideal situation. Unfortunately, not everyone does that, and even dumping a bunch of links under a 10-page post filled with copied text is enough to avoid a plagiarism ban.
he's one of the problematic nonsense troll account
In that case: report his posts for trolling. That's a violation of forum rules too:
3. No trolling.
I've seen people get away with a lot of trolling though. Freedom of expression prevails.