The fairer sex is said to have better fine motor skills, so they'd naturally be more adept at detailed work like soldering.
Well that's true, but as always, don't mix statistics and individual samples. A given woman may have very poor fine motor skills. Not all are good. Just a numbers problem.
That said, I don't know if she was using crappy solder that didn't have enough flux or the correct flux, had the iron too cool, or what, but it was painful to watch those joints not wetting very well, and the wire lap joints - ai-yi-yi! I kept thinking "Wipe the iron tip!!!"; it looked pretty crusty through a lot of the video.
To be fair, that's the impression I have when watching many, or maybe even most videos showing people soldering, be it men or women. I don't know if it's just the fact that we're passively watching and thus, more prone to judging, or if it's a fact that actually most people suck at soldering and are much worse at it than they think. I'd tend to think it's the latter.