Likely comes down to why the incubators even care, and why they do seem to allow (and with telepathy facilitate) revealing to limited muggles. Is it that masquerade helps them to trick girls into contracting, and small scale its not enough of a problem compared to meguca goodwill?
There is the easy argument that the masquerade suits the Incubators purposes by preventing potentials from knowing what they're getting into, and increasing the chances of witching out by putting on them the strain of keeping everything secret from their loved ones, while also trying to find hours a day to hunt monsters without being noticed, making sure there's no way to get help from veterans they don't know exist and so on.
However, there's also the possibility that past meguca have actually requested the masquerade. While ideally revealing magic would result in sympathy, every meguca making informed wishes/contracts, getting counselling, co-ordination with veterans, free training and weapons, a way to use abilities for money/the community and understanding when they start skipping school/work/social events... It might not have worked out that way. For mundane girls, it's another category they can be judged by ("Sophie gets better grades than you
and she spends her spare time saving lives by suplexing man-eating monsters
and her wish was to selflessly ensure abundant harvests for this town. Why can't you be like that?"). For the magical girls themselves... Every time there's a Witch-esque death, they get blamed for not trying hard enough, even if it wasn't actually a Witch or they were busy killing a
different Witch. They get pressure to use their abilities for the family/public good - at minimum all meguca can heal - slowly and expensively, but they can. Why aren't they using that to help people? Why aren't they using their superhuman power to fight for mundane causes, like the righteous suppression of/defence against the foul [nationality]? Why aren't they helping with disaster relief/prevention? Why are they sitting at home watching TV when they could be saving lives? Or making money for their family?
And dear Madokami, the
Wishes. How much scorn do you think would be heaped on the stupid, selfish girl who Wished for beauty or cake or healing a cat, instead of immortality and perfection for mankind? Or what about the (side) effects of Wishes? Does prosperity for one group ruin another? Do they
think it did? Kyouko performed mass mind control with hers. W
hat else could these girls do? Suspicion is fun! And if these Wishes derive their power from the emotions of the Wisher, then making considered, altruistic, impersonal Wishes might end up with weak magical girls, or just not work, so it's not actually possible to live up expectations.
And, of course, it's not actually viable to have a perfect survival rate. Without a Sabrina, meguca are dependant on Grief Seeds. If they all get training and work together to minimise casualties and share Seeds
and are actually proactive and successful in hunting familiars.... they'll run out. They either hoard and be blamed for letting someone's daughter die, or they share and all end up Witching out or being killed due to insufficient magic.
The masquerade may benefit QB via uninformed girls, but not having it either for families or for the public may have lead to some
incredibly toxic situations in the past, so someone asked for it, and kind little QB set it as the default.