Actually you are right, the ban (i.e. clause 3.3.2) that was there since the beginning was not against all interpreted code. Originally it said:

"An Application may not itself install or launch other executable code by any means, including without limitation through the use of a plug-in architecture, calling other frameworks, other APIs or otherwise. No interpreted code may be downloaded and used in an Application except for code that is interpreted and run by Apple's Published APIs and built- in interpreter(s)."(emphasis mine)

However it was changed, with OS 3.0 SDK I believe, certainly before the OS 4.0 SDK changes, to its current wording:

"An Application may not itself install or launch other executable code by any means, including without limitation through the use of a plug-in architecture, calling other frameworks, other APIs or otherwise. No interpreted code may be downloaded or used in an Application except for code that is interpreted and run by Apple's Documented APIs and built- in interpreter(s)."(emphasis mine)

I still maintain my position that for quite some time now developers should have had no expectations to be able to write applications for the iPhone in Ruby or Python, or some other interpreted language or at least to be able to distribute them through Apple's app store. Although in reality there seem to be plenty of applications in there that have some scripting component or another.