The baper desher loks should read Ibn Batuta before blabbering how poor Bengal is and how rich the Arabs are from oil money. One of their very own from their baper desh visited Bengal and wrote what he saw.
Ibn Battuta - Banglapedia
en.banglapedia.org
I think it also comes from his own fear that BD will absolutely leave the rest of S Asia behind and his belief that Pakistan was in any way comparable to BD, let alone "superior", will be soon blown away as BD economy races ahead of the rest of S. Asia.
If BD is much superior to Gulfies that he thinks is superior to Pakistans, then of course BD must be superior to Pakistan and Pakistanis.
Multiple bad reasons of history means that BD somehow has ended up as poor as the rest of S Asia when throughout history it was far more advanced and wealthy society.