There are a lot of things with the Pinochet regime I cannot defend. His 17 year autocratic rule could not be defended. Here is however what can easily be defended:
1) Pinochet's toppling of the Allende regime was both LEGAL and NECESSARY to save Chile from either a Cuba-like regime or civil war. How was it LEGAL? a) Allende was deemed a criminal by the Supreme Court for violating the constitution. b) the opposition had signed a treaty with Allende before he took office where he accepted that the military should be allowed to remain independent in case Allende violated the constitution. So Pinochet only took action based on the ruling of the Supreme Court and the agreement which Allende himself had signed with the opposition. How was it NECESSARY? Communism had destroyed many countries all over the world, and Allende had already plummeted Chile into hyper-inflation. Had Pinochet not intervened Chile would surely have collapsed, either into a communistic dictatorship or into civil war.
2) Pinochet treated the situation in Chile as that of a war. He regarded communism as a threat that would destroy or enslave the country. The experience with ALL other communist states has WITHOUT EXCEPTION shown that communism is absolutely lethal. Pinochets war against communists was therefore equally necessary and justified as a war against Nazi-Germany.
What part of Pinochet's regime cannot be justified? a) he stayed in power way too long. Destroying the communist threat only took at the very most 5 years, probably much less. He should have returned the power to civil rule much sooner. b) he started out with the traditional corporatist regulation of the economy inspired by Franco in the first 3-5 years of his regime. This meddling in the economy was uncalled for and prolonged the problems of Chile's economy unnecessarily.
Fortunately for Chile a) Pinochet pragmatically tried out the economic liberalism of the Chicago boys and b) when Pinochet finally did return Chile to civil rule, the civil government deepened the reforms started by the Chicago boys under Pinochet, and as a result Chile's economy boomed when civil government returned. Today Chile is, despite its turbulant recent past, the most prosperous nation in South-America and it has the lowest level of poverty in all of South-America.
But still it is very sad to know how much both Allende and partially Pinochet did to destroy Chile's economy. Chile lost at least two decades of economic growth. Imagine where Chile had been today in terms of economic prosperity had Allende's disaster never happened. Imagine if the Chicago boys had been allowed to reform the economy already in 1973, by purely peaceful means. Then Chile would today be among the richest countries in the world with close to zero poverty. THAT's what Allende (and partially Pinochet) robbed from Chile.