"But the definition of what living things deserve rights and respect is based on how similar they are to humans! Human life is indeed the gold standard here for 'valuable' life. Also, you and Singer do not reject speciesism: you say it's okay to kill things without a central nervous system (e.g., plants). Your position seems internally inconsistent to me: if you say, 'reject speciesism', that means your argument applies to all life, and the moral thing to do is starve to death. If you say, 'we can distinguish between forms of life worthy of respect and rights and those that are not', you're engaging in the exact same reasoning a meat user does; you just draw the line between living things worthy of rights and living things not worthy of rights in a different place."
It's a matter of discerning the morally relevant characteristics and then treating beings who are alike in the relevant respects similarly. For Singer, being "alive" isn't in and of itself a morally relevant consideration. This squares with common intuition. For Singer, the capacities to think and feel are the only morally relevant considerations. That's right, but perhaps more controversial. Singer consequently goes on to argue that if it's wrong to force unnecessary hardships and suffering of various sorts upon humans, it's also wrong to force the _same_ (or comparably similar) sorts of hardships and suffering upon animals. Even if Singer were wrong (he isn't), the arguments are free of inconsistency.
-- Luke