Link to the petition. We already have over 9600 votes, but we need way more to make it work.
Because Sega has been focusing more and more the PC, bringing several games, new and old, to the PC. 2 of their biggest franchises(Football Manager and the Total War series) are mainly PC games.
-Why these games?
Vanquish and Bayonetta were chosen due to being games developed by Platinum Games.This developer made Metal Gear Rising and managed to make a solid port to the PC this last january. This version was easily one of the best game ports made by a japanese company in the last years and shows that their game engine can work pretty well on PC. It also should be a better bet to ask, since both of these games sold more than MGR, so it wouldn't be much of a stretch for ports of these games.
Virtua Fighter 5 already runs on Windows/Linux on their arcade machines. The PC port shouldn't be all that harder.