I know myself that I find it just irritating if I get praise for mediocre work, which should be plain to see for anybody who care that it isn't anything special.
I don't know Bangladesh culture but I would expect that there would be similar mechanisms at work. They don't want unwarranted praise. They wanted when they have performed well.
I am guessing because from when I lived in the US, there was one thing I could find common ground among all other foreign students whether they were Japanese or Spanish and that was that American optimism and positivism is a bit alien to everybody. Don't misunderstand I think it is quite admirable that Americans are so positive and can-do attitude. The rest of the world could certainly learn a bit from that. But as with most things there is always a flip side of the coin.
Sometimes Americans seem to hit the wall of reality a bit too hard because optimism was running a too high compared to what was realistically possible.
It's interesting to see the differences anyway.
Anyway interesting with the BD colleagues of yours. I am most familiar with Vietnamese. I can't remember anything in particular about their view on criticism. But they preferred very detailed descriptions of what they were supposed to do.
When you go to a good music instructor, for example, you're paying for the well reasoned criticism, although encouragement is also vital. The masters can give both, in the right proportions.