I've not seen this happen on other fora- some new account signs up purely to post a spam URL, but in these cases it's a human who has taken the time to write a plausible post that's vaguely related to the thread topic.
Whenever I've seen this anywhere else, it's just been a generic cut and paste marketing spiel, often in caps. So it's interesting to see that the spammers are making a bit of an effort to come across as plausible, but it's still weird. I do wonder how these spammers are remunerated.