I understand why the "v-sync = 30 FPS" conclusion was made, since most people have 60Hz monitors, but it is incorrect. Enabling v-sync through the game's menu will cap the FPS at half of whatever your monitor's refresh rate is. So if you're on a 60Hz monitor the cap is 30 FPS, but on a 120Hz monitor the cap is 60 FPS. On my 144Hz monitor the cap is 73 FPS.
I don't have a source but I have tested it extensively on my computer with a 144Hz monitor. Based on this I removed the key point in the opening (it's not a "negative" anyway, since even on a 60Hz monitor it's easily fixable).