Maybe because Afghanistan is going through a tough time right now? Call of the other countries mentioned have their own cricket board and have their own sponsors. But we all know Afghanistan went to play the T20 world cup depending on the money of Muhammad nabi himself. So I think if any team needs financial support right now it is Afghanistan.
Facilities like gym, running tracks and machijes that are associated with any sports are well established in countries like Netherlands, Ireland and Scotland (which is part of ECB). So it won't be fair if you giving same funds to Afghanistan, Zimbabwe, Netherlands and Scotland. The less developed countries where not essential Facilities are available should be given more of share then developed one.