Well firstly I have to say that the girl was clearly not complying with the officer.
If she wasn't wrestling with him, he'd have never had to get his taser out in the first place.
Yes it appears she did hold her hands up but literally a split second before he tasers her, so fast that the fact she put her hands up barely registered given he was fighting with her moments ago.
In fact, if I were him and struggling with the girl at close quarter like that, I'd be shitting bricks she'd go for my gun or taser. That may explain why he decided to bring it to a head quickly to stop him or anyone else getting hurt.
He probably wasn't aiming for the groin but hey, that's what happens when you have to fire a weapon. You don't always hit the target you intend.
To be honest I've seen far worse on Youtube and everytime I have to wonder why people think it's ok for someone to fight with the police but freak out when they get tasered?
Whenever I've spoken to the police (and i've even been arrested), I've always been polite, respectful and I've never been pepper sprayed, truncheoned or tasered. Oh I'm not white either in case someone thinks its a race thing.