well since the flare is attached to the bumper I think you should ask yourself, what should you do with that bumper. I saw scrap the whole thing and get a steel bumper from one of our great vendersThen you wont have to worry about the bumper OR the flare! TaaDaa!!
Ok, seriously now.. I would take it off and see if you can kinda force that side of the bumper down a little bit. Might take some prying and wedging. Realistically there might not be anything you can do without putting some time and effort into it, including taking the bumper off etc, etc... If that is the case then I say just leave it be.