On one hand, I agree with the message, I am aware that many pirate sites steal managaka's AND translators' work, inundate their pages with ads, and profit from others' efforts. At least MangaDex is non-profit, credits the translators, and directs readers to official translation websites when available.
On the other hand, I would support manga artists more often if they had a Patreon or another direct way to receive money. When I see the author of Berserk passing away for being too busy to take care of himself, Oda complaining about deadlines and lack of sleep, and the author of Hunter x Hunter suffering severe health issues and unable to work due to the strain of his past work, I feel that supporting them by buying from publishers doesn't help change the system. I would prefer a more direct approach, like with Webtoon, where the author receives income directly from the readers and can set their own deadlines and schedules. The current manga publishing system is predatory, and unless you're part of the big three publishers' monopoly, your chances of success are minimal. Even if you are part of the big three, you'll be forced to work under extreme conditions, and if your manga isn't attracting enough attention, it might get axed.