First you're assuming a certain level of intelligence and then using that to argue from authority; that the arguments put forth on news.yc are somehow "better" because of this assumed intelligence of the news.yc commenters. I'm sorry but each comment and argument must stand on its own merits and the facts, it cannot rely on the supposed intelligence of the commenters.
Now let's get down to the real business of your arguments.
> Freedom to contract is always a good thing
This is only true if the people signing the contract are not coerced, whether by force or by poverty into signing that contract.
> Freedom to contract is a human right
So then you agree that it's a human right when it's not coerced yes?
> Government has no legitimate moral power to remove that right from people
It does if you follow the social contract. It does not remove the right but it does impose restrictions that follow from other human rights. It definitely has a legitimate moral power to impose restrictions. Whether you consider governments in general to be legitimate or moral is up to you but in this case? We have loads of precedent showing that in certain cases it has been absolutely necessary for governments to impose restrictions on contracts. Not to mention that we have courts, which you do not address. Are courts the only place where the judge or jury of your peers has a legitimate moral power to remove or impose restrictions on contracts?
> I have local knowledge regarding both my costs and my benefits from signing a non-compete contract.
Quite an assumption to make.
> Government legislators and bureaucrats, at some great remove, has almost no knowledge of either my costs or benefits.
I can agree with this though it would have to be supported; they do collect all sorts of data so they may have some knowledge, greater than "almost no knowledge".
The argument against non-competes is that they place limits on freedom of speech and freedom of expression. They put a limit on employment options as well and are harming my future earnings which are very much real in contrast to the imaginary losses. Willingness to sign a non-compete is not a competitive advantage for employees, it's the equivalent of saying "I am willing to be treated like a slave" or "I will work for free". It's degrading and violates fundamental human rights. You cannot be in support of less restricted commerce and still support non-competes. You cannot be in favour of fundamental human rights and still support non-competes which take away or immensely restrict those rights.
Your arguments, in the end, contradict one another. I will not comment on the arrogance of your approach here.