I'd say fuck rhythm too if I'm not a designer. But I am and it's my job to look at things others don't look at. You can look at a 4-pixel rhythm as 8-pixel, 16-pixel or 32-pixel. 4 is just the lowest basic unit.
Maybe I'm wrong but right or wrong isn't the point. Making people think and talk about something is.
"I hope once Likables and Denso goes live they will be proof for the production-worthiness of the 4-pixel rhythm. I also hope that Apple will see this and perhaps reconsider the visual proportions of UI in future iOS versions." doesn't match what you just said ;)
What I'm saying is that "You can look at a 4-pixel rhythm as 8-pixel, 16-pixel or 32-pixel. 4 is just the lowest basic unit" doesn't improve upon our situation. The lowest basic unit is called a pixel. Grids make everything look consistent; but when the only requirement is that you snap to 4-pixels, things aren't going to look consistent, because you have far too much flexibility.
Maybe I'm wrong but right or wrong isn't the point. Making people think and talk about something is.