what makes astrology and lycanthropy work?

Too wet to walk, too shallow to sail, I’m where frogs sing loud and reeds prevail.

Inside its farmhouse, you must steal its white pearls, lest its owner eats it first.

I demand attention, reject it once it’s given, blame you either way, and stare at you like you’ve failed life itself. I stay close, but only on my terms. What am I?

A term that comes for the Greek for milk, I'm kind of a big deal, The milk thing is weird, since if you were coloring me in, the black crayon gets the lion's share of the meal, But from afar, even with the massive size of stars, they appear as little points, of white, or whatever, light, Further away still and a you'll see the spilt milk, right?