Right to work actually is a restriction of contract law; that's why the name is so misleading. It's one of those Right Wing call-something-the-exact-opposite-of-what-it-actually-means type of phrases (think "Clear Skies" or "Healthy Forests" Initiatives from the W days). What right to work laws say is that companies are barred from signing contracts with unions that (a) allow for union dues to be extracted from the company directly, and (b) that make union membership mandatory. Again, it's a law that tells private parties what they CANNOT do with civil contracts.
I have no background in contract law, so please humor my ignorance. Is it not possible for contracts to be void when they impinge on the behavior or rights of non-signatory third parties? If I draw up a contract with my sister obligating my mother to bake us a cake every day, surely that can't be a binding contract? Forgive me if that's an egregious disanalogy.
Hold up, b_b : aren't there myriad restrictions on contract law that we condone? Consider minimum wage, currently set at $7.25/hour (federally). If an employee wishes to contract to work for an employer at $2/hour, Congress interferes and "tells private parties what they CANNOT do with civil contracts." It seems unfair, or inconsistent, to attack right-to-work laws on the grounds that they restrict contracts when you spare all other such restrictions the brunt of your attack. Or perhaps you do in fact deplore minimum wage (or any of the other thousand examples) as a restriction of contract law?
Yes. Of course there are many restrictions on contract law. Many of them are for all of our benefit. One can make an argument about whether RTW is good or bad. But in your original comment, you framed it as granting more freedoms. It does not. That is a fact, not an opinion.