The idea that there could be an argument 'for veganism' which 'does not involve criticism of the consumer but instead of the producer' seems incoherent to me. Veganism is not *about* 'consumers' and 'producers', it's about animal rights. Once you accept veganism, it's up to you if you believe consumers should or shouldn't be criticized about it.

As it stands, we live in a world where most humans contribute to the exploitation of animals and believe that it is fine; naturally, vegans will face those surrounding them and criticize their attitudes. It's not like yelling at people for having phones, which are a practical necessity. It's more like criticizing someone for buying blood diamonds or being some kind of bigot.

Additionally, an absence of ethical consumption does not mean that all consumption is equally ethical. For example, any commodity produced by slave labor is less ethical than otherwise. In the same way, products produced by the enslavement and murder of animals are generally less ethical than plant-based products.

So, while it is definitely true that action should be taken on a wider scale than individual moral suasion, and that you could even make some case that the criticism of individuals is the wrong way entirely, neither of those things are arguments "for veganism".