Alas, that's not always true. Indeed, sometimes shedding light on — paying attention to, calling out, providing publicity for — the fringy and freaky only lends them credence, makes them feel important, that they've arrived. It can even validate their feelings to be publicly berated by those they hate/fear/mock.
But whether the dark things can or can't stand the light, sometimes the light is necessary to confirm they are there, and to let them be revealed to everyone for what they are.
The Alt-Right’s Dark Army of Racist Trolls Just Had a Great Day