I didn’t leave it out, it wasn’t there.
First of all let’s take a step back - this text is from a decision made by an appellate court regarding a decision made earlier in a custody trial. It was not their goal to retry the abuse claims or review the criminal investigation into the allegation of abuse.
They relied 100% on what was given as testimony during the custody hearing. They didn’t interview witnesses, they didn’t view exhibits of evidence or talk to investigating detectives.
Immediately after the point where you stopped quoting, they went on to say more.
Let’s look at the whole quote so we see the complete thought they were trying to convey in context:
I’m not sure how you’re interpreting this to be these judges finding “other corroborating evidence of abuse”. What it is saying is that there was testimony in the custody hearing that suggested there was abuse. Of course there was. There was also testimony given that suggested there wasn’t. They concluded this train of thought with the line you left out of your quote: “While the evidence in support of the allegations remains inconclusive, it is clear that the investigation of the charges in and of itself could not have left Dylan unaffected.”
So looking at the paragraph in it’s entirety, what they are saying is “We can’t discount the testimony given during the hearing that suggests Dylan made it all up. And we can’t discount the testimony given during the hearing that suggests it actually happened. What we can say is that, either way, this isn’t good for the kid. Simply having had the charges made against him, true or not, and the resulting investigation, and the impact this has had on the family, we agree with the previous court that it isn’t in the kid’s best interest to change the custody arrangements they decided on.”
There is no question that the appellate court made very clear they disapprove of his relationship with Sun-Yi and basically think he’s a horrible father and a self-centered prick. But the thing you’re quoting doesn’t say what you think it says about the allegation of sexual abuse.
And, back to the original point, it is and was the single, only, allegation ever made before or since. Your quote from the appellate court is talking about evidence that was given in regard to that single, only allegation, however you choose to (mis)interpret what it says about it.