Professionals get it wrong sometimes. Judges go on the information they are given. But that info can easily be not the whole picture.
Of course they do - there are, in all professions, individuals who aren't very good at their jobs.
In this case, there have been literally dozens of professionals involved. Medical experts, psychologists, guardians, social workers (both LA and CAFCASS).
What is the likelyhood that the are all wrong? That each time Rebecca made an allegation, the professionals who investigated that case were wrong?
I accept that there are times when overworked and stressed professionals may not look at closely at a case as they should, or make assumptions based on previous experience - but in this case, Rebacca has provided professionals with many different opportunities to investigate Ethans circumstances and in each case they have all drawn the same conclusion.
What is more likely; that the various different independent professionals have all made the same repeated mistake over the last 3 years, or that Rebecca was trying to manipulate the system? Her parents have, after all, admitted that she ran away in order to manipulate the press.