I spend a good bit of time in Arya III talking about how the Kingswood Brotherhood is dark as hell, how the Brotherhood Without Banners is morally ambiguous, and the modern history of political kidnappings, so no, I don’t think I romanticize them.
That being said, ASOS sets out why people in the Riverlands support the Brotherhood Without Banners, because no one else is stopping monsters like Septon Utt and the rest of the Bloody Mummers.