But I do know other women who use that voice... and every one of them has a similar reason for doing so... appeasing an adult, a male! Playing up to stereotyoes, not being strident or loud to do so. So, regardless of her personal reasons for adopting it it does represent a certain kind of behaviour for many people!
I am extremely soft-spoken. I do not have it in me to be strident or loud. As a result, when speaking in the company of males, whether in a private or professional environment, I am regularly interrupted and some loudmouthed man (usually; but some women also do this) barge in and take over the conversation.
Also, I tend to wait politely until someone has finished speaking even if I have something important to say that contradicts what they are saying, before I put in my own argument. But invariably, some male interrupts instead, cuts the other speaker off, and I don't get the chance to say my bit. This is annoying. The answer might be to become loud and strident myself and do the interrupting before anyone else. But how would that help?
BTW I don't think I have "that voice", but my voice IS very quiet. But I was not raised to speak quietly. It's just the way I am. My mother was an extremely prominent and outspoken feminist even back in the 50s. famous in my home country. After she died I found umpteen photos of her in an official function, the only women in a pack of men, looking very confident and calm. People always listened to her, and she had a commanding voice. I don't, but certainly not because of my upbringing (Mum was a single mother, one of the first in my country, and Dad did not raise me at all).
So you too are saying you find it hard to listen to women who speak quietly, because they represent a stereotype. What a way to marginalise such women yet more! My advice is, LISTEN to them. They often have something worthwhile to say. Don't let a soft voice dilute or obliterate the message -- that's what men traditionally do.
There's absolutely nothing wrong with soft voices; if it gets on your nerves like chalk on a blackboard, maybe it's time to ask why; why do you want women with important things to say (like this one in the video) to be as strident and loud as men have been conditioned to be. Why are some of us impatient with female stereotypes (soft, gentle, polite) but not with male ones (loud, strident, rude)?
I'm actually the other way around. If someone interrupts a conversation with some loud, long comment of their own I stop listening. Sorry this post was so long. It just turned out that way.