Also, is there any evidence that the Derg spent the Live Aid proceeds on weapons, or was the BBC lying about that report?
Speaking of the BBC, a Newsnight piece a few years ago said that the EPRDF under Meles was also committing a kind of holodomor, in the same way (by withholding western food aid from areas of Ethiopia that supported the opposition parties). Is there any evidence of that?
Once again, please refrain from lay speculation, I don't want the comments to be nuked by mods for being unsourced. This is an answer I've been wanting to know for almost 5 years.
Short answer is yes.
The Derg made policies between 1978 and 1983 that had the practical effect of making farmers more susceptible to famine.^1 These policies arose out of the Derg's desire to provide a sufficient food supply to the urban populations of Ethiopia, keeping food prices from rising and provoking unrest in the cities.
These policies included empowering the Agricultural Marketing Corporation to set quotas that each region must produce, shortfalls in the harvest would not trigger a reduction in the quota, and this effectively left farming families with just enough nutrition to survive.
Additionally, heavy taxation to pay for the war effort, to pay for the RRC (an agency intended to prevent or remedy famines like the one in 1974), for road building, for literacy campaigns, and fees for school, for membership in the Peasants Association, Womens Association and Youth Association; all had the effect of forcing peasant farmers to sell off livestock and grain stockpiles, taking away a traditional safety net in the event of crop failure.
Thirdly, the Derg introduced policies to regulate grain traders, wrote laws against "hoarding" and "profiteering" in the grain trade, and closed or limited the hours of operation of village markets. These policies were partially motivated by the Dergs marxist ideological hostility towards markets and traders, but also motivated by a goal of directing harvests towards the AMC by strictly regulating the private trade.
Specifically in the Tigray region in 1982 and 1983, the armed forces of the Derg are accused of burning villages and grain stores, killing livestock and destroying orchards, as a way of destroying the peasantry that the TPLF relied on for their insurgency strategy.^2
In the period from 1984-85 when food aid was being delivered, there are numerous credible reports that the government in Addis Ababa protested and actively tried to shut down shipments of food aid to REST (a relief agency tied to the TPLF) and keep food out of regions controlled by rebel groups.^3
Additionally, there were substantial reports of food aid in government-controlled areas being diverted to feed the military, especially members of village militias that were pressed into service but were not supplied through the regular organs of the military.^4
So, there has been a good deal of scholarly work that comes to the conclusion that the Derg did much to lay the groundwork for the famine, and then followed policies that punished peasants in rebel-controlled areas and made the famine worse.
1 Evil Days: 30 years of War and Famine in Ethiopia 1961-1991 by Alex De Waal, Africa Watch (a division of Human Rights Watch), 1991. Chapter 9 pp 155-174. Alex De Waal is a well respected scholar of genocide in Sudan and the Horn of Africa, and I relied heavily on this book throughout this answer.
2 Ibid, pp 138-150.
3 "Ethiopia: Political and Security Impact of the Drought" a CIA intelligence assesment published in March 1985. pp iii, 5-6
4 De Waal, pp 187-190