They're scraped and most likely added to (shared) lists XRumer can get.
It was a tactic I used for blog commenting way back when (when it worked and was profitable) using a scraper search "Powered by WordPress" to do automated comments with another program, posting comments written in another program that could spin text (now you have AI that can "spin", but it took time to spin unique comments
{{Good morning,|Good afternoon,|Good evenening,} {all readers|everyone|all who came here}}... to get random comments like Good afternoon, all who came here -- except I sometimes went 4-5 levels deep).
