Having lived abroad for 17 years as an American, I have found a very strong correlation between those who can not understand a thick accent, and those who can not communicate well with non-native English speakers. No idea if this is the case with Paul, but if you have actually spent the time communicating with a wide range of non-native speakers, you are much better at understanding and making yourself understood. I think all you non-native English speakers know exactly what I mean.

Communication - a two-way street. That is why Paul's comments strike many as tone deaf!