I certainly wouldn't blame the IOM, and they were not being at all "anal", it is great that they accept FAA licences at all, and they were most apologetic about having been "leaned on" by the FAA over this requirement.
They are the most "user friendly" people I have ever come across. I had the privilege of flying the very first M reg international flight in MELON and have been flying and operating various M reg a/c ever since.
Once MI gave me the "translation" of the FCC website, it was a doddle - but I would still be struggling now if it hadn't been for him.
If you're bored, have a look at the FCC website and try and imagine you are trying to get one of these new fangled R/T licences!
BWs
Jez