Credit: Soul Brother/FilmMagic

One person who's not keeping close tabs on Jessica Simpson's weight ups and downs: her little sister Ashlee Simpson-Wentz.

During a Wednesday appearance at the Hershey's Store in Manhattan's Times Square, Simpson-Wentz, 25, shrugged when asked if folks are too hard on her big sister's body. "I just don’t get why it’s such a topic," she told

At a Jan. 15 press conference for her VH1 reality show The Price of Beauty, Jessica, 29, admitted "I haven't always had an inner confidence, and I haven't always looked at my reflection and loved it."

Simpson-Wentz also demurred on the topic of Jessica's new friend Billy Corgan. "Oh gosh," she said. "I don't think I'm going to go there right now." Jessica and Corgan, 42, went on six dates before calling off the romance earlier this month. ("They're working on being friends," a pal says. "Jessica is proving to herself that she can be pals with a guy she used to date.")

Married to rocker Pete Wentz with their baby boy Bronx, 14 months, Simpson-Wentz is optimistic for Jessica's romantic future, despite her rocky past with the likes of ex-husband Nick Lachey, wacky musician John Mayer and football star Tony Romo. "She's my sister!" Simpson-Wentz said. "I want her to just be really happy."