Well of course, she doesn't design the clothes herself because she's a singer and songwriter not a fashion designer. But she decides herself which of their clothes to wear and for her tours she directs them on what type of costumes she wants and they do the actual sewing and technical part of designing. There's no one in the music business who does everything themselves because you can't be good at every task. But she is in charge and is the leader sort of like a movie director. A movie has a costume designer but the director decides what they want the costume designer to design.
Well, then, you are agreeing she doesn't do it all herself then and that is what that post I quoted was talking about. She's not some wonder woman media mogul, she employs people to do jobs for her, that includes stylists and designers. Also if you honestly think Madonna is any position to tell Jean Paul Gaultier what to do rather than what she likes, I've got some chocolate fireguards to sell you. However picking what she like doesn't make her a designer or stylist. It makes her a customer with preferences. If I buy I Ralph Lauren shirt I like, that doesn't mean I am styled by Ralph Lauren, it means I am wearing his style of fashion.