This was also the first thing I thought. Sketch is a well-known (artistic) design tool. I'm sure you fellas already know that but decided to stick with it anyway. In reality, it really doesn't associate with your product all that well, definitely not when compared with the photoshop-Sketch and what it's for.
Agreed. Honestly, when I first saw it I got excited because I thought it converted Sketch files to RN files (what it is is pretty cool but the name totally threw me for a loop)
Not to mention the numerous results from Google SketchUp and Autodesk SketchBook that popup when you're searching for "sketch <help-me-with-something>"
I'm a designer at Twitter and our design team has been using Sketch for UI design for the last few years. I believe the same situation occurs at FB and many other design teams unless doing very particular photo work or iconography/illustration.