@Dunnas Fair point, fine, for fictional characters, an author can assign any age, so perhaps that's not a reliable standard. I shouldn't have pointed that out as my reason for griping about the show. So, in Slave Harem in Labyrinth of Another World, Roxanne has the proportions of a grown woman. There's another character in that anime, Vesta, who is apparently 15, but if you take a second to look at her appearance in the anime... what kind of 15 y/o typically looks like that? So the age is arbitrary when it comes to anime, because most characters are supposed to be drawn cutesy usually, and characters are drawn and aged younger, even though their proportions might actually be wildly different. It's what the character looks like, what they could be a depiction of in real life, that I would say matters most.
Another example that comes to mind of age being unreliable for anime characters, Jotaro Kujo from Jojo's, what kind of average 17 y/o looks like he's been in the Marines for years and is 6'5"? In another classic ecchi, High School DxD, Rias and Akeno at least look like they could be in college, proportions-wise and stature-wise, despite their assigned canonical ages. I believe Akeno is 17 at the start of the series, and Rias is 18 anyway to start out with. And that show actually has more substance to it than constant sexual scenarios, those are frequently done but there's a reasonable balance between actual substance and plot, and fanservice. I also watched Mushoku Tensei, where characters are accurately and realistically sized for their ages. Another controversial show apparently, but there's so much more to the show and it's more nuanced than just a few tense or questionable scenes here and there, and any scenes like that simply fit into the narrative and make sense for the growth and maturity of the main characters, they're not just merely fanservice.
So again, my point for all these examples is, my standard, where I feel the "line is that makes something wrong and something perfectly fine," is based on a character's appearance, if they actually look like they could be a depiction of a grown adult, a pre-teen, a college-age student, etc. That's what I usually go by. You have the "3000-year-old-dragon" meme argument that's typically used, but if the character looks like a depiction of a middle-schooler, that's definitely a no-go.
Now, looping back to Gushing over Magical Girls, no, I haven't watched the show, but just by perusing reviews and descriptions and all that, and looking up the ages and seeing that pretty much every single female main character is 14 and they actually look, act, and appear like their age, and that the main selling point of the show is all of them getting sexually harassed this way and that, BDSM everywhere... as well as the fact that this ecchi show is mostly just that throughout... I feel that, for that reason, Mato is the more defensible and reasonable show. Y'all can watch whatever you want, but I simply found it incredibly funny that this was even a thread in the first place.