You're clearly mistaken. Synthesis isn't my preferred ending. And who said anything about heretics? The Quarians and Geth were in conflict centuries before ME1.
Ghehe. Maybe synthesis was not your thing, but your were clearly present there. The rhetoric didn't change, though,
Like always you turn stuff upside down to safe your posts. You were telling me that the geth rebelled. Well, they did not. Here is why.
The geth were defending themselves after the quarians were trying to shut them down, because they showed sapient behavior. It resulted in the Morning War, where in the end the geth did not exterminate the quarians, but instead isolated themselves beyond the Perseus Veil for the next three centuries.
The geth we see in ME1 were some geth, which were infected by a reaper virus. These geth were known as the heretics and split off from the other geth. And those are the ones we fought. The other (non-heretic) geth, were bothered by that. They started to investigate the reaper situation, organics and eventually found Shepard. In the mean-time they preserved the quarian's graves and cleared their home planet, without occupying it.