From their description, we can easily assume site M is mangadex.
Going after the sole legitimate scanlation site is the dumbest idea ever, considering there have been many instances where manga sites have collaborated with scanlators from there to provide legit translations; and the scanlators often does stop releasing when an actual english release is available digitally in a good pace with japanese releases.
Fuck them so hard. Fuck Kakao. Literally one of the most evil company in South Korea. I can do a whole speech about how shitty Kakao is and how much I hate them.