There's still a stigma that marketing somehow equals snake oil salesmanship. It's supported by myths that certain products became immensely popular without any marketing that ironically you read about in media that promotes the same product.
Marketing and programming map to different personality types. You program a machine, alone, and it's predictable. Marketing is based on understanding and dealing with people, their needs, emotions and inner drives. No wonder our first geek reaction is to shy away.
But in my experience most people with engineering background who are given the job of marketing, eventually understand what's the deal, and either become what it takes or find and support someone to do the job well.