Not an excuse, but the reason I can explain.... which I am sure will go 10 feet above the head of BCB idiots.
BD players play Test at home with Kookaburra - a ball notorious to create havoc when new for first 23-25 overs, but looses it's sting by 25th over. Besides, machine stitched Kookaburra is never suitable for spin based attack for it's low seem, once worn out and it doesn't swing much when old, let alone reverse. BUT, these same players play domestic FC cricket with English County Grade balls, not that low in quality but it never offers the same venom like a new Kookaburra. For that, our top order is always under pressure and by the time Kookaburra looses it's sting, 4/5 are already back in hut - they simply can't handle the extra kick & movement of machine stitched hard & shiny Kookaburra, made for Australian tracks. Couple of years back, before T20 got better of him, Shaheen won couple of Tests in his first spell.......
You'll see despite being relatively docile wickets compared to SAF or UK, still new ball produces among highest number of wickets in Bangladesh, not only against hosts, but against tourists batting as well, while bottom half always has produced runs - even Bangladesh spinners often run through top half of the side within first 25 overs when it's bouncing & kicking off the surface, only for bottom half to pile up runs. In recent times in PAK, they used same Kookaburra and we found scores like 25/6 to 260+, 100/4 to 560+ ... Some genius will say that reverse the batting order - Liton as opener, Miraz at three .... result will be 89 all-out, trust me - because the problem is different.
It's not that batsmen are incapable, but batting is a precision, zero tolerance job - need to make just one mistake after 2 hours - our batters are doing one in every alternate new ball overs!!! We need to bring one change to counter this - either play every FC game with Test grade Kookaburra, or change home Test ball to Dukes, Test Grade 1. I prefer the second as it'll make the spinners more effective.
What I wrote is cricket explanation - rest you can credit to bad blood (gin), brain fart, lack of talunt, hopeless nation ..... options are endless.