No, semi-automatic rifles are primarily built for hunting and\or target shooting. A simple investigation on the number of times they are used for those purposes vs any other purpose would confirm that. In much the same way that a simple investigation on how often cars are used to transport vs how often they are used to kill would indicate their designed use.
And would not the builder be the authority on what the purpose of their device is? After all, they are the ones who are building it. How would you prove otherwise?