“Changing a law to charge someone after the fact and bring him to trial is called an “Ex Post Facto” law which is unconstitutional.”
The problem is that this is not a criminal statute, which is to what the prohibition against ex post facto laws applies, just like the prohibition against double jeopardy only applies to criminal trials. You can’t be tried for the same crime twice, but you can be sued more than once over the same incident. I’m not saying it is fair, but it is reality.
Thank you for clarifying.