We state in our blogpost that we make an exception for Obama/Trump in order to raise public awareness. Both of them are regularly used in Machine Learning benchmarks (for example [0] [1]). Note that we don't allow users to generate from Trump/Obama's voice.
Once again, we care a lot about these issues and that's why we only allow users to copy their own voice.
[0] http://www.washington.edu/news/2017/07/11/lip-syncing-obama-... [1] https://www.youtube.com/watch?v=ohmajJTcpNk
These issues are challenging and suggestions about how you think the technology should be introduced/regulated are very welcome.