I honestly didn't bother watching the behavior panel, 4 white dudes with skin in the game (ie money to make off these vids) turned me off instantly and then I read into their background and wasn't impressed.
Body language swings so easily into pseudoscience because it paints with broad brush strokes and doesn't often treat itself with scepticism, ie its proponents usually believe wholeheartedly in their own conclusions and that this press of the lips here means xyz when in reality someone could press their lips together because they have a coldsore coming or they just farted and are hoping no one notices.
There are way too many variables in any given situation to give anything more than a maybe to any body language interpretation. It can be useful sure, but it's not concrete, guaranteed, able to be proved / disproved, with massive variables in play and hence is known to be unreliable. Making money off it muddies the waters further.
Actual doctors and therapists know not to armchair diagnose and not to comment on those they are not treating and have never met. But the internet is awash with these 'experts' making money doing exactly that. And no one can argue against it cos it's special sauce magic whatever.
As for Harry contradicting himself - sure that could mean he's lying, manipulating or being manipulated. However having worked with victims of domestic violence it is not at all uncommon for victims to speak positively about their abusers, to minimise or deny harm as a way to survive, or to not even recognize abuse until it's so severe it lands them in hospital. Humans are complex, trauma and toxicity causes people to act / think / speak in unpredictable ways, it's not all just rocking in a corner crying and cringing. I've seen women absolutely in love with their partner who beats the shit out of them.
So yeah - when someone claims an abusive or toxic relationship, and acts unpredictably, contradicts themselves, acts against their interests, speaks positively about someone who hurt them and then speaks negatively - it's kinda par for the course and it makes me more likely to believe there's some truth in it. Maybe not the whole truth, but some. Situations are multifaceted, relationships even more so. It's not as black and white as simply who's lying and who's telling the truth.