Looks like Apple have put a grey mask on the icons, that's why they show as colour in finder view and grey in the sidebar.
It's so frustrating and for visually impaired people like my parents, it's the difference between being able to use the OS or not.
I love the full screen options & extra gestures in Lion, so making it so difficult to read is just terrible.
Making everything look the same doesn't make it more 'refined' or 'professional' at all. There is absolutely nothing professional about a GUI that's difficult to read - that's just utter nonsense.
Please Apple, give us an option to have colour icons back in the finder side bar, just a checkbox is all it would take, then EVERYONE would be happy.
Thank you
PS: Please put the sidebar icons back in the correct positions too. The Devices Pane shouldn't be at the bottom of the sidebar, it should be at the top! 😟