Yes, she wore black turtlenecks...according to reports, every day since the company was started. Why does being photogenic matter? Because you're more likely to have a massive photo spread/cover devoted to you. Steve Jobs himself was very photogenic. But Theranos is much more affected by Holmes as the face of the company. Because the company never talked about its tech in detail, there wasn't much else to focus on except the youth and passion of its founder.

Those were reasons why the media and public are interested in it. Yes she does wear black turtlenecks. I'm sure the way she dresses is part of why people are so interested in the stories. It's probably largely schadenfreude, the kind the celebrities are usually subject to when they put on weight or get arrested.