It is true that a handful of Jagex Mods have left the team recently (I heard Mods confirm this in Mod Mark's FC), although it is only speculation at this point that the SoF was responsible. Atleast as far as I'm aware.
I agree that the backroom situation at Jagex is quite interesting though. I believe that there are probably a good number of Jagex employees who strongly oppose the SoF update, yet are unable/unwilling to speak out or act out on it. After all, they earn their living at Jagex and it would be unwise to just up and quit over the SoF.
If it was in fact true that Jagex Mods were quitting the company in large numbers because of the SoF, I would be quite proud of them for sticking up for the spirit of the game we all love, and for helping to voice the concerns of the playerbase. As of now, it appears we have been ignored on the RSOF completely (even though when asked, this is where all J-Mods will tell you to take your feedback so it can "be dealt with"), and so maybe having employees leave the company over this issue will help open some people's eyes about what is at stake here.