Eating fish or lizards on the other hand, is a lot harder to amalgamate to eating mammals ... ie. it's easier to go "awwww ain't that cute" when seeing a calf breast-feeding but harder to say the same thing when seeing a lizard dump eggs in the sand somewhere and walk away. Eating birds ... I don't know, it kind of sucks too ... they go tweep tweep, are (mainly) monogamous, care for their little lones ... so that should make them prone to "awwww ain't that cute" syndrome too.
I just don't think I get the whole "I'll eat this mammal but not this one, which is man's friend (or man's cousin)" thing.
In my philosophical view, if you can farm blue whales you are welcome to eat them, but I think there is a decent argument for opposing them becoming extinct just because you like their flavour.