I have no problem with Bangladesh gaining access to US military tech and arming itself to defend their country. Every country has that right. However, everything US does in the region is based on containing China's rise and so any defence purchases will come with obvious strings attached. The more Bangladesh becomes dependent on US military tech, the harder the US will push for Bangladesh to join its containment strategy against China and adopt anti-China policies. China in turn will have to change its approach towards Bangladesh, which at present are cordial and economic ties are booming.
Bangladesh has to decide if gaining access to US tech is worth annoying an emerging superpower, in China, on their doorstep and risk of cutting itself off to China's huge growing market which Bangladesh will need for its economic development, not to mention investment from cash-rich China. US intentions with regards to Bangladesh are probably no more than recruiting another potential proxy state that will bear the brunt of China's wrath, to further their geostrategic policy of containing China. China has shown with countries like Canada, Australia and India that they will not sit idly by when hostile countries are acting against their national interests.
I'm sure Bangladesh has no intention of upsetting China but when you bargain with the US Devil, the Devil will expect you to do his bidding. Putting yourself in between two warring superpowers is not an enviable position in my opinion.
BD economy is dependent on the US and the west in general.
China is merely a market for us to buy from. We do not sell much to them.
BD need not get involved in a china containment policy but if push comes to the shove than it will.
You are seeing things from PK-China prism. China is not a friend to BD as the rohingya debacle has proved.