Because, again, he wasn’t convicted in criminal court. And again, there is a different burden of proof in civil cases (preponderance of evidence vs. “Beyond a reasonable doubt.”). There are many reasons why a case may be brought in civil court and not criminal.
One famous example is OJ Simpson. Ruled not guilty of murder in criminal court, but lost in civil court and had to pay Ron Goldman’s family a fuck ton of money, as well as giving up any profits he may have made, or ever will make, based on the murders (that ridiculous book, etc).
Not enough evidence to convince a jury in a criminal trial, but more than enough for civil.