I never really liked Horner, but I am glad he was cleared, because I just have to believe someone in that position in F1 would not use "controlling behaviour" to a staff member. I know that that is bit hopeful, but anyway.
On the other hand, if you are going to accuse the leader of the currently most successful team in F1 of controlling behaviour you would surely provide some evidence. Controlling behaviours is very broad term, in fact almost meaningless in the context. But for RedBull to publicly launch an investigation it means they must have felt it was serious.
The whole process has done RedBull no favours. It is strange that they announced the investigation, but other than that we have no further information. Not even a conclusion to go along with the outcome. There is something odd here.