While often these comparisons are good illustrations to make people see certain things or think about animals in a different light, I think at the same time we have to be careful with them and not only see the similarities, but also the differences.
I think there’s a particular problem when peoeple use the parallel with human causes to justify NOT fighting for incremental improvements.
This is how it goes:
A pragmatic activist says that he’s in favor of certain reform regulations, such as a ban on unanesthetized castration of piglets. Others (Francione and his “abolitionists”, for instance) might counter with something like this (this is an actual quote from someone):
Would anyone advocate for the abolition, or the regulation, of child sex slavery? All of us would say it is our moral obligation to advocate for the absolute END of child sex slavery, and that “improvements” are wholly inadequate, and speciesist.
The same people may make arguments like: we would never campaign for “humane rape”, and: it’s not ok to just have wife beating-free wednesdays (referring to Meatless Mondays)
I think the comparison here is very shaky at best (and that is putting it mildly). Child sex slavery, rape, or beating your wife are things which 99% of people will disapprove of. Killing animals for food is something at most a few percentage of the population disapproves of and the rest not just condones but actually celebrates. Obviously, issues with such dramatically different public support require different strategies.
In general, I think we should be careful with drawing parallels between the animal issue and other (human) social struggles. Let’s not lose sight of the differences which are relevant. When we do lose sight of them, it may blind us and we may believe we could apply exactly the same tactics or communication style, while better ones may be available.