If a law a government writes saying this is ok, but this isn't is your standard then you'd be supporting some reprehensible things. Slavery for example. Just because something' legal doesn't mean it's moral, just as something being moral doesn't make it legal. Rather we have to see things where human beings are a part of the chain of life and not special class exemptions to it. We're part of nature, not a separated class outside, above, or alongside of it. Thus if killing some animals is acceptable because it's legal, any animal's fine. When you begin pick and choosing which are ok, or when or why it's ok you loose the whole arguement becomming hypocritical.
I love animals, I risk evictionfeeding squirrels and duckies here every year, however I don't try and rationalize it by saying some animals by virtue of being cute and cuddly are more deserving of my love than others.