At the LSE-blog (politics and policy), Terry Hathaway argues that ethical consumption is "dangerous to the values ethical consumers seek to promote".

According to Hathaway "[t]he seduction of ethical consumption comes with the idea that making purchasing choices is akin to voting", and he clearly dislikes Friedman’s idea that acting on the market is similar to voting in a democracy.

Sure, there are obvious differences between buying stuff and voting in a democracy. But when Hathaway goes on to explain why ethical consumerism is different from voting, almost all of his examples are cases when ethical consumerism is strikingly similar to voting:

"ethical consumption is akin to voting in a system where many of the desired goods are not available for purchase"

Correct, but so is voting is a democratic election. Many positions that a particular voter would like to vote for may not be supported by any candidate or party.

"A consumer may buy a hoover that was made with limited pollution seeking to ensure clean air for instance. However, they will not realise their interest unless everyone else makes similar choices."

Correct, but this collective action problem applies to voting as well. The policies I vote for will be implemented only if enough voters vote the way I do.

"Democracy is not a system whereby everyone makes their own choice and the outcome for society follows from these individual choices. Democracy is where the views of both majorities and minorities are aggregated (with, ideally, conflicts between different interests being resolved in the process of this aggregation) in a system of collective decision making"

Actually, an aggregation mechanism will not resolve conflicts between different aspects. Rather it will generate a collective decision based on individual choices. Furthermore, we know from social choice research (Arrow’s theorem) that the aggregation rule may very well result in paradoxical or seemingly irrational outcomes.

I agree, however, that a free debate in a democratic society will ideally resolve conflicts between different interests, and generate better decisions. Ethical consumerism may well be part of such a debate.

"Even the most hyper-vigilant, well-informed shopper cannot know everything […] the consumer must buy in partial ignorance"

Again, correct. And again it applies to voters as well. We buy, we vote, we simply act in partial ignorance.

"there is a degree of ambiguity in just quite what or who you are voting for by purchasing something that complicates the idea further. For example, buying a Fairtrade Nestle KitKat from an Asda works as support for Fairtrade, support for Nestle, support for the particular product and support for Asda […] a consumer’s "vote" for a particular product may support one of the consumer’s values, but it could also equally (and simultaneously) support a value they oppose"

Again, correct. And again, the same goes for voters in a representative democracy.

"if consumer are the ones determining the market then corporations are effectively non-actors (or heavily-bounded actors) who do not take decisions in terms of production, marketing and retail in line with their financial bottom line. This discourse thus presents a bizarre inversion of reality, whereby consumers are collectively responsible for corporate decisions, rather than corporations themselves"

This, I believe, is not correct. Consumers determine only demand, market outcomes are determined by demand and supply. Of course, one can on ethical grounds question both what (some) consumers are willing to pay for and what (some) suppliers are willing to sell. The same goes for politicians and voters.

"purchasing as voting is a weak feedback mechanism at best and there are other actors who are able to influence the system."

Correct again, but correct for both ethical consumerism and democratic voting.

In my opinion, the conclusion that ethical consumerism is dangerous to the values ethical consumers seek to promote, is still correct. The reason, however, is the general pattern that good intentions sometimes have unintended consequences.

I believe that Hathaway is right about the reason for such unintended consequences. As he nicely puts it, we all act in partial ignorance.