Reasons for leaving the Hasbara narrative behind
There are plenty of reasons to leave Hasbara behind.
Personally I could I first started leaving it 25 years ago, or that I never really fully believed it. Believing the arguments to be bad and being against the dehumanisation that was required. One could leave Hasbara on principle alone and this might be the more "noble" one. As if there's some hierarchy.
One could also leave it from personal testimony. For example seeing the treatment of Palestinians (as has happened to me in a minuscule way as per the above link). Of course what you see is filtered through your pre-existing commitments so you probably need to have some level of groundwork. But some people who are commited to the modern mainsteream Israeli view can and do leave it behind after seeing enough on the ground.
One could also leave it because they believe in the overwhelming consensus of expert opinion. For example on the illegality of much of Israel's actions. Or on the truth of the Gaza starvation blockade, or the documentation of war crimes. I suppose that's still a fairly intellectual reason to do it.
One could also leave it from seeing what it's doing and done to Jewish life. For example how the exponentially expanding definition of antisemitism hurts Jews both practicaly and in terms of soul/place in history. I suppose that's a more selfish reason but again I don't think we should be quick to judge. I don't think there's a better or worse way to leave behind believing falsehoods. Focusing on purity has rarely helped make the world better. And so I don't want to poo-poo pettiers reason for leaving Hasbara.
One reason I've had in the last 6 months is self-image. You see, the reasons and justifications that are given are so ludicrous that anyone giving them must take me for an absolute fool. And I don't believe that I'm a fool. Being treated like one makes me feel disrespected.
Yes it's horrible to weight this against the tens of thousands (or more) who have been murdered and the millions being starved right now. However a person's self-image is more salient for them than pretty much any external event. And a petty reason can be a good reason. Of course if I think Hasbara talking points take me for a fool then I'm already predisposed to not believe them. But pettiness can help drive action and help the mind reach a certain state of decision-making that might not have been reached with the non-petty brain alone.