Why are all the backlinks to this article from weird coupon sites?

I subscribed to the SEMRush trial and I'm learning to use it. I heard one SEO technique is to look at where the backlinks to current high ranking articles are coming from, and then use cold email techniques to try to get them to replace that article with yours (or add yours as well).

To explore the 'Backlinks Analytics' feature, as a case study, I typed in 'How to grow your twitch audience' into Google and grabbed the second article and tried to analyze it. I found something strange. Nearly all the backlinks were coming from weird coupon sites, all of them super bearbones bootstrap, clearly generated URLs.

Example of these sites:

couponsdance[dot]com/

couponstrong[dot]com/

mycouponsearcher[dot]com/

What is going on here? Is there an intentional technique being leveraged to boost page rank?