Some these seem to be "handling charges" relating to DHL paying customs duties in advance & then recovering them from the recipient. I suspect some national post services also do this - the UK Royal Mail certainly used to. So perhaps there's not much to be done about this kind of charge.
However, some may to relate to DHL's policy on 'remote areas'. I doubt many national postal services levy similar charges (which could be interpreted as discriminating against rural etc populations).
The ideal solution would be to encourage RS to offer delivery by ordinary postage. But until that option is available, here is a way to check if you're in a remote area and likely to be saddled with a large unexpected bill
