Actually that stem looks very steeply angled - flipping it would probably be too much of a drop, so I can understand keeping it in that position.
Since I use long stems (generally 120 mm), I tend to go for flatter ones (+/- 6 degrees). When you have a stem that long, even if it's relatively flat, flipping it will move the bars 2.5 cm vertically, which is quite a bit.
But don't listen to the style police, pick (or keep) the stem length/angle that is the most comfortable for you.