As far as the point of donkey being harām (forbidden to eat) is concerned, if I am not wrong, there are many opinions out of which one emphasizes the point that domestic asses only have been declared harām and not all categories. But my point, on which I wish to get clarified, is that there are some narratives which clearly indicate that the Prophet (sws) had made domestic asses harām for consumption, when he was informed that they were being eaten at the time of a campaign and when the Muslims were in dire need of transportation facility provided in form of these asses. If this is agreed, then do we still have to consider such domestic asses as harām. Please note that in many parts of the world asses have been replaced by cars etc. So, does the consumption of domestic asses still have its stand in form of forbiddance as it was exactly during the times of the Prophet (sws).
As you may know, the Book of Allah, which is the final version of Divine Law, does not provide us with an exhaustive list regarding what is halāl (allowed) and what is harām (forbidden). It maintains a clear stance that Allah has allowed us to eat everything which we, in the light of innate guidance, hold lawful. The Qur’ān reads:
They ask you [O Muhammad] what is made lawful for them. Say: pure things are made lawful for you. (5:4)
The Holy Qur’ān has only proscribed four things about which mankind was not in a position to adopt a clear stance. The following verse while mentioning this proscription also asserts that every good thing is edible.
Say, I find not in that which is revealed to me anything prohibited to an eater that he eats thereof except it be carrion or blood poured forth, swine flesh for that verily is foul or the abomination which was immolated to the name of other than Allah. (6:145)
I think what needs to be appreciated is the fact that every human being earth knows what is edible. No one teaches a lion how to hunt or what to hunt; he never goes for an eagle or a crocodile. Similarly, a vulture always prefers to feed on carrion; it never goes for a flying bird to first hunt and then eat. The case of humans is no different. They inherently know what they must eat and what not. They would never place on the dining table an eagle cooked in corn oil or a lizard barbecued with spices. They like to eat what their Lord has ordained within their souls as permissible to eat. Therefore, there was no need to give an exhaustive list of what is edible and what not. Allah has only proscribed the above mentioned four things because mankind could not have decided their status regarding eating.
Seen in this perspective, domestic donkey is not an animal to be eaten under all circumstances since human nature abhors the very concept of eating it. The majority of mankind has never taken donkeys as edible though a very nominal minority must have deviated a bit. Such people have always been corrected by their society as the Prophet (sws) corrected some of his Companions (rta) during the campaign. Hence, the proscription does not hinge upon whether they are domestic and are being used for transportation.