Are laws and constitutions themselves a violation of the 14th amendment? Can the government deprive people of their liberty to use drugs for recreational use, hire prostitutes, gamble, etc? Any law places a restriction on someone's liberty, correct?
No. The 14th Amendment says no person may be deprived of life, liberty, or property without due process of law. There's an argument the legislative procedure must meet certain requirements, but the fact it was passed is certainly capable of being due process (and normally would be due process).
Yes and no. If a law is unconstitutional, its enforcement is against the law. So you can break the law, and then successfully fight the charge on that basis. But it won't feel like liberty when you're arrested, jailed, etc. Also, whether a law is unconstitutional isn't always clear, so the courts might decide against you no matter how strongly you believe you're in the right.