I read it not as sarcastic, but as carrying an implication that the Firefox leadership is intentionally tanking the browser - that their conscious active goal is to sink the ship, and that the drop is a result of malevolence rather than incompetence. And I suppose that would imply the person in the image believes Mozilla is being run by people who don’t want the browser to succeed.
I haven’t really followed the leadership at all, nor have I always agreed with the anti-Mozilla stuff I see annoyingly often on Lemmy. So to be clear, I wasn’t agreeing with the linked post, just giving my interpretation of their intended meaning.
I appreciate the added context you gave. I don’t think I’ll ever understand how a website full of so many people who love free software can be one of the most anti-Firefox places I’ve encountered on the internet. It often feels disingenuous or astroturfed.