Swiftfox developer Jason Halme writes on his site, "the licensing restrictions were put in place to safeguard Swiftfox users against the possibility of obtaining tainted versions from anyone who may wish to maliciously alter the binary and redistribute it." But this in itself is a security concern. Normally lots of eyes would be on the code -- the files would be inspected as the application was placed in a distribution's repositories. Now, instead, new users are asked to trust the lone developer.
The developer has every right to license his code in whatever way he chooses, but there again we have a problem. Swiftfox isn't a fork, it's a build. The person who compiles the Swiftfox binary simply changes a few graphics and changes the license; the code isn't changed or improved. He then draws in new users who may think that the application is free. It is free in cost, but not in freedom.
Most Linux users prefer FOSS applications because we can take the code and use it, modify it, share it, and improve it. We don't like it when someone takes those freedoms away. Apparently some people don't think about this when it comes to browsers.