Some of you may be wondering why the judicial system has such a strong respect for precedent, being often reluctant to overturn rulings that, in hindsight, seem clearly wrong. It's a little easier to understand when you see the other side of the coin: what happens when those precedents are changed. When a precedent is overturned, what the case law on a particular topic once said now says something different. Previously legal actions may become illegal. People who have made decisions based on the prior rulings may find that their actions are now illegal, forcing them to reevaluate their decision -- and in the case of physical objects or past behavior, they may find themselves in legal jeopardy that they had no way to effectively predict.
Gun control laws, being intended to regulate physical objects, are particularly vulnerable to this effect. What was legal yesterday may not be legal today. Or it may be legal, but under a grandfather clause requiring the owner to prove he owned the firearm before the law was passed. Or the law may come with registration requirements, so that the firearm remains legal only if registered -- and registered firearms may become illegal and subject to confiscation later. Worse, most gun control laws come with significant penalties. Who wants to become a felon because their legislature banned something they purchased years ago, or some bureaucrat decided to change their regulations to forbid something previously allowed?