This is Bootstrap, through and through. You’ve set everything up correctly except for the collapsing part of your nav. If you added the
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"> and closing tag around your
ul, you’d find that your links would disappear.
This is because Bootstrap is trying to make the navigation “mobile-friendly”. If you open up the display window (by dragging the middle bar) or change the view to full page, you’ll see a horizontal nav.
My advice is to add the collapse features of the bootstrap nav.