It’s not he said/she said if Fox feels the need to offer a public apology.
This doesn’t settle this quickly unless there are witnesses and hard evidence in the form of recordings.
Carlson did record Ailes.
A media company going out to cut off bad press by issuing an apology isn't necessarily evidence of culpability. It is evidence that they want this story to go away.
That said, the preponderance of the evidence indicates that Ailes is a no good louse and I judge him so, even if there are no legal repercussions for him.