I think it's all being taken a bit literally on here, yes you can ask for Angela and ok most people know what that means, but surely what it's trying to do is make women aware that that particular establishment are happy to help if you're in a situation you're uncomfortable with. That can only be a good thing.
At the same time let's all look out for each other too, few years back I was in a train station late at night going home from work, young girl sat alone, group of drunk men standing way too close on an empty platform, they kept looking over, talking quietly, she looked super uncomfortable so I went and plonked my fat arse next to her, asked how her day was etc, chatted like we knew each other, she may have thought I was nuts but the blokes moved away. We shouldn't have do this shit but we do.
Also this 'put your big girl pants on' if you're feeling uncomfortable doesn't always work, I could have easily said to those blokes to move away but what if it escalated?
So yeah i think it's just a message to women to say if you feel uncomfortable let us know, there's no way it could ever have been kept a secret code for just women, but overall it's a good message