Yes, I guess so QS, though I always had more the parliamentary underrepresentation in mind for a march/demo. The anti-violence against women protest - can't argue about that - but it seems quite generalised and non-specific. It's like marching in favour of world peace, almost. No one is really quite going to be against it, so it's a case of so what then? Must admit I hadn't quite heard of that march you link to in The Guardian, but that's my lookout.
Also, it talks about being against male violence against women, nothing to argue with there, but you've got half the population rightly or wrongly feeling a bit guilty and awkward right there hearing/reading about it. A march against a specific grievance helps eliminate that as blokes will think, right no way am I like the specific instances mentioned.
Now, why should anyone care if blokes feel that way anyhow? Fair enough, but it seems across the board that if you have a power group and you are trying to change that, then vested interests - whether they see it that way or not - are not going to be too obliging. It's almost as simple and straightforward as male golfers barring female members. It's a case of when and how it gets to a tipping point.