I think it's really a difference about whether you approach meat consumption as a moral issue or an environmental and social one.
I tend to agree with @Melpomene that any improvement is a good thing, maybe a better analogy would be in CO2 emissions. If we can convince 10% of people to bike to work one day a week then that'll make meaningful difference, and it's exactly the same from an emissions standpoint as taking X cars off the road.
Convincing someone, at least in the USA, to do without a car is fundamentally difficult, but convincing them to use it less is a significantly more accessible proposition.