FWIW, when I refer to the willingness of others to see things through the lens of Mollie's killer and I refer to the the remark about a lifestyle-threatening event from his perspective, I mean this, and only this, with no add on about "excusing" him:
I do not embrace the idea that anyone concerned with keeping LE away then engages in behavior that risks drawing attention from LE - like trolling and following a jogger, and then having the audacity to get out of this car (his story) and run after her. I believe this behavior is that of a predator utterly unconcerned with getting caught or being outed as lying and being here illegally. I also believe that his reasons for following her were the reasons of any predator - to find and gain control of prey that the predator is going to end up harming for his own selfish gain. Also, I do not subscribe to any theory that all predators look or present a certain way or that we can see them coming, or that they all plot their crimes. They are by nature opportunistic, however smart or stupid they may be in the commission of their crimes.
I also think that in regard to this person, in some cases and across a number of platforms, understanding why he did what so many like him do has entered the arena of a lean toward sympathetic consideration of his background, language history, cultural shortcomings and other factors that we don't even know pose obstacles for him. We spent a lot of time on whether or not a translator in his interrogation and two more translators in court were enough for him to understand what's happening to him and why.
Sometimes people don't need a reason to kill the person that's found dead other than, as Otto said, it's what's gratifying to the killer. To that extent, I don't think Mollie's alleged 'threat' to contact police was his issue - other than it potentially interfered with ability to carry out his mission, should he be interrupted. So he likely swiftly incapacitated her, took her, and the rest is whatever investigators can piece together, because he's never going to give that up. To me that doesn't make him a clinical study, it simply makes him a reprehensible violent coward who wanted both his victim and the shroud of secrecy. JMO