One of the big questions is, considering what an 'orientation' is supposed to be, how can pedophilia not be considered a 'sexual orientation.' A framework of laws, including judicial precedent, is being set where it is going to be very hard to argue, legally, against the idea of discrimination against someone with 'pedophile orientation' working in a Kindergarten. This type of discrimination should definitely be legal. Those with known 'zoophile orientation' should be subject to legal discrimination when it comes to working in raising the livestock used for producing the meat we eat, either.
Logically, you're right. But our laws are not based on logic. They are based on the opinion of the legislators and the people at large. People are fine with heterosexual sex, obviously, and are even fine with it out of wedlock. People did not want to be "trapped" in marriages, as of old. If Olde England had our divorce laws, Henry VIII need not have troubled himself with Reformations and decapitations. He would have tossed out the one and got the next in a couple of weeks.
The society has reached the stage where the bulk of people no longer care who beds whom, male or female (human is still a requirement, for now), as long as both humans are of age and give consent. And in general society cares but doesn't much punish two humans, of whatever sex, who are below the age of consent as long as both are.
And so we have gay "marriage", and we have very little virginity by the time college is through, and we have easy and frequent divorce. These are all things that society, in its state of emotional tolerance, is comfortable with.
Society still has a fetish about the number TWO, however. Polygamy was practiced all the way back to ancient times in virtually every society, and is widely practiced today in the Middle East and Africa. Our society is not emotionally willing to accept what we collectively see as barbaric. There are lots of "reasons" given, but what it comes down to is "We don't like it, and we have the power to say no, so no."
The same is true a fortiori for pedophilia. Sure, many pedophiles have no control over their feelings. They want what they want and they can't "help" it. Their only choice in the matter is whether to act on those feelings. And as we know from heterosexual and the broadly expanded homosexual experience of the population, and the experience with serial divorces, and the experience with gradually legalizing marijuana, and the drive to pan-obesity in the population, people are very poor at impulse control. Pedophiles "can't help it" without exercising a degree of self-control that our whole society has found itself unable to exercise. We've changed the divorce laws, the marriage laws regarding gays, and the drug laws to accomodate what "we" want as a public, and what we are no longer willing to subject ourselves, as a collective, to punishment for doing.
Obesity is its own punishment. Nobody wants to be fat, it's not illegal, and it's brutally hard for people to avoid it, and brutally hard for those who are to lose it and stay slim. Because it is unpleasant to look at obese people, as a society we still vilify being fat EVEN THOUGH well over half the population is.
Pedophiles are no different in any of these respects from heterosexuals, multiple divorcers, homosexuals, pot users and the fat. So LOGICALLY we would make allowances for their wants - "they can't help it", and we understand it.
But, simply put, we hate what they do. We hate pedophilia, we hate polygamy, we hate incest, we hate heroin use, and we hate inappropriate behavior with animals. It DOESN'T MATTER that, logically, these impulses are no different from the legal ones, and that, "by the same logic" we would be on the path to legalizing all such impulses. The fact remains: law is not determined by logic or by a computer. It is decided upon by people, and it is based on human emotions. What we want or like, or can tolerate, we legalize. What we despise, we outlaw and punish. It doesn't matter that the people we punish "can't help it". If they can't help it, then they are rabid dogs who need to be removed from society, and the law does that for us.
That it's "unfair" to those people that THEIR weakness is punished while, say, the gays, or the divorcees, or the pot users, or the serial fornicators, are not, is irrelevant, really. Sure it's unfair. So what? It ain't about fairness, it's about power.