Nor do I really; most of 'em look fantastic either way. But it also really depends on the person; different people suit different colours, and sometimes they pick one that doesn't suit...
I don't mind either aswell but I sometimes prefer natural colors even if they're dyed tho there are some idols who can really pull off well extreme colors such as blue, green, silver etc.
just saying.... when do you ever see your idols with ACTUAL NATURAL hair? the most is they dye their hair the closest shade.
since their hair is all bleached usually