No, Sith usually don't embrace the light side and I think that view is just Palpatine's. Their similar views are why some think that Snoke is really Darth Plagueis. Another reason is that Palpatine sent many probes and scout ships beyond the edges of the galaxy, searching for the source of his power. Lastly, Pablo Hidalgo was asked if Plagueis is still a Muun, and he replied with, "or better yet, still dead?".