You're referring to the Official Code of Georgia Annotated (OGCA).
https://arstechnica.com/tech-policy/2017/03/public-records-a...
The Official Code of Georgia is available online for free. However, the Official Code of Georgia Annotated is not. The law itself is not copyrighted, merely the annotations. The annotations are produced by private companies (Westlaw and LexisNexis), but are considered essential for legal research purposes. So although they are private written works subject to copyright, they possess something akin to but somewhat less than the power of law.
Most if not all of the major obstacles to full public access to case and statutory law arise from the LexisNexis/Westlaw duopoly over legal research. Courts historically have relied on the companies to collate and publish the reporters containing all the significant judicial opinions, rather than incurring the costs of typesetting and publishing the opinions themselves. They also publish annotated versions of the state and federal statutes and administrative regulations. The annotations make them copyrightable, but also provide added value to legal researchers. Lex/West then turn around and charge enormous sums of money for access to these reporters and annotated codes and to their searchable databases based on those. Many citizens are thus unable to access legal opinions which set common law precedents or statutory interpretations binding as law on those citizens.
Even where the opinions are published online for free by the court, e.g. Supreme Court opinions, lawyers rely heavily on the cross-citation services and topical annotations provided by Lex/West. Raw opinions and statutes just aren't that easy to use for research purposes without a fairly intense indexing system. So even though a lot of law is available for free online, it's hard to make full use of.
A few firms, like FastCase, are trying to produce relatively cheap/free alternatives to the traditional services, but it's extremely difficult to collate and annotate the massive volumes of judicial opinions, administrative decisions, rule makings, and statutes generated at the state and federal levels each year, never mind historically.
On the other hand, it's probably worth mentioning that the more significant a law is, the more likely you will have free access to it. Most inaccessible laws deal with small jurisdictions or narrow issues. Or they require a strong legal education to understand and apply. You may not be able to find an opinion issued by the California Board of Equalization in a 1973 tax dispute about what constitutes constitutionally sufficient notice of a propose adjustment to taxes owed, but the issue is so obscure and technical that access isn't really valuable to the general public anyway. The costs of providing access to that law are more efficiently allocated to the rare individuals who need it than to the general public. Those individuals pay their lawyers who pay West/Lex, who bear the costs of preserving and organizing these legal texts. Or so the argument more or less goes.
Really, this whole debate cuts to the core of the legal profession. Why should people have to pay a premium to ensure they are complying with the law or to resolve a dispute or to defend themselves against charges from the state? Which is really another way of asking, why is the law so complex that an elite caste of specialists is required to administer it?