Heh. I used to feel the same way. Over long years of thinking about it, though, I started to understand ... well, that there's a body of larger issues that can't be described in only a few paragraphs. 

I'll address only a couple of points:

"...it is certainly immoral to curtail the freedom of a (human) citizen in favor of an animal."

Then why do we have RULES regulating fishing? I mean, why not let everybody fish with dynamite? The success rate for the fisherman is hugely greater with dynamite than it is with some measly fly, on a silly 3-pound test line.

Funny thing is, if you were to ask around, you'd find it's FISHERMEN who are most strongly opposed to dynamiting fish. Why? Because they know that dynamite would spell the end of the enjoyment of their sport. In a very short time there wouldn't be any fish ... at least not in any place that sport fishermen could easily reach.

Lest you miss the point, protecting fish from dynamite is, in the opinions of a majority of fishermen and concerned others, GOOD FOR PEOPLE.

Ditto for this idea that animals are "our slaves." Ahem. Why do you suppose it's (most likely) illegal to beat or starve a dog where you live? It's because most people know that animals are ... not exactly property, in the sense that a skateboard or a sweater (both fully, no-questions-asked, disposable objects) are.

Sure slavery sucks if you're a slave. Anybody can understand that. What most slaveholders can't understand is that slavery sucks for the slaveholder too. Treating beings (or creatures) like disposable property, when you know they have feelings, has a totally unavoidable negative impact on YOU ... and the people around you. This is not some airy-fairy, touchy-feely idea, it's the real deal: If you damp down your faculty of compassion and understanding, it's damped down for everything. The amount of it you have available to lavish on your wife, your kids, your fellow man, is LESS. 

Outlawing slavery doesn't just benefit slaves or potential slaves, it benefits EVERYBODY. Any society with slavery is a crueler, more callous -- and, interestingly, economically poorer, less adventurous, and technologically more backward -- society.

From the inside, the worst thing about slavery is being a slave. From an outside perspective, though, the worst thing about slavery is what it does to the slaveholder and by extension to his entire society.

Okay, we're not talking about slavery, exactly, we're talking about animals, and our relationships with them. The point stands: treating animals ONLY like slaves/property is not good for US. (There is, for instance, strong evidence that most adult psychopaths were once children who abused animals.)

My having said that is not license to jump to a "Okay, let's give them voting rights and jury duty" argument. There's a very broad range of compassion and care possible in between the two extremes. The fact that PETA stands closer to one of the ends of that compassion-spectrum than probably most of us doesn't mean their arguments are TOTALLY without merit. I'm not a member of PETA, for instance, but it's also true that nobody gets to beat a horse in my presence without me doing my best to stop them. 

I have a couple of longish essays that go into some of these points more fully. Shoot me an email at woofster2@usa.net and I'll direct you to them.