The problem is not that she found the terrorist hot. That is completely fine, people who do evil can be attractive (Despite what Disney would have you believe). The problem is not having that internal observation, but in putting that out there into a public space. What's the motivation behind doing THAT? Do you want to pull people into a discussion about giving praise to this person? Talk with others who are reeling from the tragedy about the physical attractiveness of someone constantly reminding you of murder? None of these things are appropriate, and feel like they are trying to mitigate the crime, and at the end, it seems like the suspects, "Hotness" has become a piece of evidence that he may be innocent. And given the tone of the video, the background music, and the general language she used, its pretty clear that this is not intended to be a complicated, philosophical question about how we view attractive people. This was the sort of thing you keep to yourself.
In comparison, imagine that a person made a video about how much they enjoyed a very specific poop, and shared that on youtube. Sure, it can be relieving to poop and thats all well and good, but you probably shouldn't share that information. Because it awkwardly makes people think of your gross poop. Now, replace reminding people of poop oversharing with reminding people of dead children, severed limbs, murdered law enforcement and blood on the streets in the wake of an IED bomb. Yeah, thats just a little bit worse.
In comparison, imagine that a person made a video about how much they enjoyed a very specific poop, and shared that on youtube. Sure, it can be relieving to poop and thats all well and good, but you probably shouldn't share that information. Because it awkwardly makes people think of your gross poop. Now, replace reminding people of poop oversharing with reminding people of dead children, severed limbs, murdered law enforcement and blood on the streets in the wake of an IED bomb. Yeah, thats just a little bit worse.