Kristen Stewart has branded criticism of her raunchy new Rolling Stone cover “sexist and homophobic”. The ‘Twilight’ actress, 33, appeared on her latest shoot for the magazine wearing only a white jockstrap and a black leather vest with her hand down the front of her crotch, which has been slammed by some on social media as an example of the objectification and sexualisation on women. Kristen said on ‘The Late Show with Stephen Colbert’ about the backlash – after Stephen, 59, brought out a picture of the cover as he revealed the series’ broadcaster CBS had requested it not be shown: “Well, oka…