I agree with you completely and used to argue something similar.
Unfortunately it's responses like the one from ArmsHeldOut that stopped me bothering.
Kind of like how anyone who objected to Perry's race change was suddenly a racist.
Now, if anyone suggests that Lois being ginger changes the way the audience views her in a steroetypical way - they are being almost as bad as a racist
There IS a stereotype.
No it's no absolute. It's not like a blonde character can't be serious and intelligent and a brunette can't be fun and stupid.
But that doesn't mean a characters hair colour CAN'T contribute to their personality in a subconscious way.
And for me, Lois' always has. Even to the point where, in Smallville, the darker her hair got, the more she seemed to act like Lois Lane the respected reporter and less like the army brat kid living in Smallville.
In fact AMY HERSELF believes there is some pre judgements made on hair colour. Which is why she dyed her hair ginger when she's a natural blonde. She said in an interview that she felt she was taken more seriously.
I personally agree. I used to be blonde, with short hair. Now I'm brunette with long hair. And there is a difference in the way people see you.
Now the weird thing is that when you look at Lois' personality - it fits a stereotypical red head.
But I kind of feel that takes something away from the character. Like she's fiery BECAUSE she's a red head, not because she's Lois Lane.