If you want to avoid becoming angry, try not to read Boff and Boff’s Introducing Liberation Theology and Ratzinger’s “Instruction on Certain Aspects of the ‘Theology of Liberation’” in rapid succession.
I mean, seriously, who the fuck decided that 1984 — i.e., the fucking peak of the death squad era — was an opportune time to slap down liberation theology tout court? (And don’t tell me he hedges, because he starts out by hedging and then shifts toward using “theology of liberation” only to refer to the bad Marxist kind that basically existed only in his own precious and balanced mind.)
I think Adam raises important concerns. Even as someone who sits somewhere in the orbit of Ratzinger's stance on this and other aspects of theology, I remain deeply uncomfortable about certain harsh crackdowns on Christian dissent, not least when such profound issues of justice are at stake as were in Latin America and elsewhere. I think that a criticism of the sort that Clodovis Boff has recently leveled (as David points out here) is the appropriate route, rather than outright censure of a clearly vibrant and pious movement in the life of the Church... and liberation theology was and is clearly that, whether or not I'm entirely in agreement with its approach.
By way of contributing to the conversation, I wanted to point out an article in the new issue of Expository Times. Deirdre McGovern's "Dissent in Contemporary Catholic Context" considers the way that the concept of "dissent" is often associated with 1) negative connotations and 2) political liberalism (a good example is the Ignatius Press blog's recent focus on the Sisters of Charity).
McGovern does a good job of exposing these misunderstandings, pointing out the relationship between dissent and reform. In addition, she argues that the main source of more destructive cases of dissent since Vatican II has arguably come not from the left, but from conservative corners that have stood opposed to the development of Church teaching. She discusses the position of CIC 1983 on the voicing of dissent (Can. 212), and the tightening (or indeed, the actual rejection) of it in the 1998 document Ad Tuendam Fidem. Ratzinger plays into this narrative as he did the 1984 instruction on Boff, this time through the commentary on John Paul II's promulgation. McGovern goes on to argue, against Ratzinger and the general sentiment of contemporary conservative factions of Roman Catholicism, that dissent is a necessary part of Catholic faith insofar as it works as a reforming agent. The essay is worth reading and helpful as a proposal for dialogue in the Church.