That's not really what's going on. The issue is that other countries have what they call '4G' networks. The iPad claims that it has '4G' but it's not the kind of 4G that works in these other countries. So by advertising that it's '4G' it sounds like it will work on the 4G network in those countries, but really it won't. It's misleading.
But again, the ITU has stated that 4G can now include older 3.5G tech as well as LTE - that the carriers feel that only LTE constitutes '4G' in their eyes is irrelevant.
Apple has been careful to differentiate '4G' from LTE. They have pointed out the the iPad will only work on a few select lte networks, but will work on other worldwide '4G' networks - it's just that carriers outside the US don't refer to them as such.
At the end of the day it would have been so much simpler if the ITU had stuck to their guns and defined '4G' as LTE and above - we have the American carriers to thank for jumping the gun with HSPA+ and WiMax.