He had every possible chance to argue his case, both against culpability and then against the specific damages, but both he and the lawyers he hired refused to do so. This 1.4b dollars was not a particularly harsh judgment coming down from the establishment (note that the establishment is the president Jones was a paid campaign member for), it was the result of his implicit acceptance of every claim the Snady Hook parents made.

What would instead have been a reasonable punishment?

Either he truly believed that the kids at Sandy Hook were actors, or he was using it as part of his grift and making money of it.

As far as I can tell he has not reversed his stance on it