I don’t believe that “created by women” or “made for female audience” is ever an excuse if the product is problematic, especially in terms of sexism.
After all, women sometimes work on the stuff we feature here (like the design of warrior princess Solange). And because those female creators internalized the harmful ideas about gender expectations, their designs aren’t inherently any better than those made by men.
As for mahou shoujo/magical girl anime and manga, they’re generally hand-waved by the “a wizard did it“ principle. The characters are magical girls and their powers usually oscillate on the edge of exaggeration, so their battle outfits aren’t expected to be exactly fully-protective armor.
There’s this popular argument that the whole point of magical girl genre is to empower little girls by weaponizing femininity: everything is designed around female appeal, so that the audience can see that a hero can be an epitome of girlishness while still beating the crap out of evil monsters.
Which of course is not an excuse for why some of those battle uniforms and transformation sequences tend to be… questionably fanservice-y.
It’s really a classic ‘childhood ruined’ moment when a little girl grows up and realizes just how absurdly short Sailor scout’s skirt were and that the sparkly transformations she admired so much were someone else’s fap fodder. Especially considering most magical girls are underage.