I think, Sarfraz is right here, but as usual his choice of words are wrong and he is still salty (regarding his "kale" jaban).
First - yes, in PAK, at least in Karachi, Bangali is used as a derogatory word. Sarfraz is right in correcting the journalist - I myself have mentioned it many times here in PP that we are Bangladeshi, not Bangali or Bengali. Bangla (Bengali) is a language that's spoken by people of 2 different countries (Now multiple - lots of Canadian, British, US, AUS passport holders speak in Bengali now, but they don't hold BD or Indian Citizenship any more), just like English is spoken by Aussies, Yanks, Kiwis, Irish, Jamaican, Barbadians .... that doesn't mean they are English or British. I have seen many ignorant posters here using the term Bengali (often as a negative sense) for Bangladesh team, which is quite unfortunate. On record, I can say that apart from very few (brain washed) Bangladeshi citizens, I doubt how many are there to be recognized as Bengali. Even, tribal people in Bangladesh speaks in Bengali these days therefore terming any National based on their language is not right.
But, by mentioning his issue (more preciously his ban), he is not showing maturity here - he is PAK Captain and got banned for a raciest slur (doesn't matter what his motive or feeling is regarding racism), it should have buried there.