I think if you read what Kato wrote, he says there were rebel attacks on the line around 1977 and subsequently (ie nearly forty years ago), but it was restored to operational state, and it ceased in 2008 not due to rebel attacks but due to the abysmal state of the line and delays by a European maintenance company. While obviously there are rebel groups operating in some parts of Africa (not least where I work, in South Sudan), I think generalisations about "the all too numerous rebel groups" are inaccurate and don't really help African countries to develop.
The guerilla war in eastern Ethiopia ended around 1981. The meter gauge line was restored to operational state (which doesn't mean it was all repaired) pretty soon but slowly fell into disrepair in the late 90s, possibly partially because government money instead went to finance the war against Eritrea. After that war, around 15 years ago, the government actually wanted to privatize the line.
The EU-sponsored effort which would have turned over operations to a South-African company after some upgrades was a last attempt to save it at that time. When this didn't come to pass, operations on the line ceased pretty quickly since - as the government didn't spend money on it - no one did any maintenance on it any more (first the Addis Abeba - Dire Dawa section since 2007, then the Dire Dawa - Djibouti section from 2010).