The officer had literally no reason to request it other than to lord his power over her. He's written the ticket, she's perfectly able to sign the ticket in the car and both of them would be on their way.
He didn't like being told that no, she wouldn't put out her cigarette. It was a perfectly fine response, since the cop has no legal ability to demand it, but the small-minded cop sees it as an affront to his authority. So, instead of letting it go, he barks an order that she's required to follow despite the officer having no good reason to actually request it, because then either he'll get the deference he feels he deserves, or she'll disobey and then he has a reason to drop the hammer on her.
If she put out the cigarette, she goes home with a warning. She mouthed off, he got pissy. Honestly not a single person knows what happens if she just got out of the car when he asked her too... maybe he just wanted to not have smoke coming out a window at him.
It's sad she died, but she didn't comply with cigarette request, then she refused to comply getting out of the car. At that point, is he supposed to just say "you know, just go ahead and go?"
That's what I don't get.. you can't just not comply with a police order. They ask you out, then get out.. they aren't going to have a back and forth with you all day about it, eventually they will force you out.
There's choices people make in situations, and sure the cop went full dick-mode when she got sassy with him.
The video clearly showed her not complying, then continuing to NOT comply after out of the car.
People here act like you should be allowed to be a dick to a cop, not comply, and just go on with life, because cops should just be the bigger person.