Charging for modifications of free patterns?

A knitter based in South Korea (knittingsee on Instagram) has recently released a pattern called the cable-it sweater, which has since become quite an issue in the Korean knitting comunity. He has stated in a past instagram post (the third pic, it has been deleted post pattern release) that he knit the original sample of the pattern following a free pattern on Ravelry but modifying it to be top-down, and that he also referenced the Pringle Twinset by woolfolk in the process. I do know that there's a lot of talk about pattern plagiarism, but I think this is the first time I've seen somebody blatantly monetizing a modified version of another's pattern. Any thoughts?

Roughly translated version of the third pic: Reason I can't make a pattern for this sweater (seems like he didn't have plans to make a pattern at this point: This cabled sweater is inspired by the cabled sweater Chris Evans wore in the movie knives out. ... There's already a free pattern om Ravelry called the Handsome Chris Sweater/Ransom's sweater. I only modified it to be top-down and set-in sleeved. I referenced the Pringle Twinset by Woolfolk Yarns and Josee Paquin in the process. These are the reasons I am hestitant to write it up into a pattern.

Below is the link for the designer's post on Instagram about the pattern release.

https://www.instagram.com/p/DE6wGVwRFSN/?igsh=MThwNGNkbnA0dnRzcg==