Britney was and continues to be very tightly controlled by her handlers. She was never allowed to control her own narrative - when people claim her to be a puppet, they're not kidding. That allowed many in the media to get a free pass for harassing her for years, because those leeching off of her knew it was often good for business to have her name out there in the press and being reported on. Her star power has died down a lot since then, so all of this can be bubbled up to the surface and dissected now.
The big difference is Madonna controlled her narrative, something Britney has never been allowed to do in her entire career or life in general. Her team crafted that virginal image around her, and then intentionally crafted the sexpot image to go in contrast to it. Britney continuously got lost in that shuffle. When she's allowed to speak for herself, Britney is often the first to say she was never comfortable with how "sexy" some of her videos and photoshoots had to be.
I remember an article a few years back talking about what a dangerous precedent it would have set if Madonna had apologized for the Sex book (like many wanted her to) and that era of her career. To this day, she never has. VICE is generally trash, but this was a good take on it.