As with urine, is it true that the darker the beer/wine/spirits are, the more impurities they contain? Wang?

Answer 1

False, just because a drink is darker doesn't mean it's more impure. Vodka is clear but higher end vodkas are just as clear and have fewer impurities. Rum is also a case light rum has more impurities than dark rum. Beer always has impurities no matter if it's a pilsner (amber) or ale (Dark). Impurities are based on the distilling prosses or fermentation prosses only not color.

Answer 2

That statement is wrong with beer as it is wrong with urine. Dark urine means you're (likely) dehydrated.

Darker beers are made with grain that has been malted at a higher temperature.