I was wondering about that, myself. I guess they don't think it's important or prestigious enough. Or maybe they are worried about security, like a couple of the players.
Afaik Cutting costs might be responsible...BBC Coverage yesterday was : Live text commentary on the BBC Sport website & app, plus regular updates on BBC Radio 5 live.
I was lucky to find that TV coverage was Free-to-air on both Sky and cable on Sky Sports Mix. I only discovered it by chance after cable was installed yesterday!
The Bangladesh Cricket Board sells its rights to a third party which then markets them for a higher price.
The demands were so high the BBC almost pulled out completely from covering the tour and by the time an agreement was reached it was too late to make logistical arrangements for the one-dayers.