Because excessive baiting and author's past brought yurifags into the equation. Having character with a dick in "their" manga is a big no-no, and usually elicits screeching. For large part of that fandom it probably comes down to something like narcissism mixed with
feeling that their
identity is being threatened or invalidated, hence the opposition followed by exaggerated reactions (which are genuinely creepy, as most of these people are at least twentysomething, often older).
Like here for example. Ugh.