but as you point out its not straight.
Also that has been bent and straightened once.
Instead of bending a bit of a pole just once do this instead, put a lot of weight on it side ways take it of do that repeatedly. Subject it to vibration, road salt, advere weather of hot and cold for several years.. Then bend it round a pole and see how well it straightens or if it crasks, I am sure you can't tell me if there are cracks appearing on the inside, or at a microscopic level or if there are now any floors in the structure of the metal where you made your bend.
Even if it doesn't break or crack from being bent once, are you going to attach a still obviously bent bit of metal to your car and trust it to hold loads on the roof when doing 60mph into a head wind?
@jrkitching is still right here, its not worth using a damaged roof rail on a car, same as you wouldn't trust a crash helmet or baby seat that's already been in a crash.