I don't really understand this point. You ask why women want to compete in sports where they will always be second class - but that's true of almost all sports, isn't it? By their very nature, men will massively outperform women in any activity involving strength, speed etc. You mention sports like hockey and netball, but I expect women will always be second class compared to men there as well, will they not?
It's not really clear to me what you mean by sports where women are the "natural audience" either. Again, you mention sports like hockey and netball, where England are an elite nation in the women's categories (and not so much in the men's categories) relative to other nations. But England are an elite nation when it comes to women's football as well. They won the Euros, whereas the men did not. And they are currently 4th in the FIFA World Rankings, whereas the men are ranked 5th. And I'd also point out that if women (and indeed men) only ever focused on sports that their nation was already good at, there would never be any such thing as improvement.
Not only that, but whether something is classed as a "man's game" or a "woman's game" is very culturally relative, rather than inherent to the sport itself. For example in the US, soccer is sometimes considered to be a "girl's sport" (in the same way that we might view netball) - probably because their women rank so much more highly and progress so much further in international competitions than their men do, and because it’s less physical than American Football. Of course the same is not true in England, where the men have also historically done pretty well, and where the men's Premier League is probably the best in the world, and where we don’t have American Football as such. On the other hand Americans see baseball as a masculine sport, whereas in British schools it's usually girls who play rounders (which is basically the same thing). Again, if people only ever stuck to sports which are culturally associated with their gender more than the other, there'd never be any development or improvement on the other side.
I think it just takes a little bit of investment in the sport at grassroots level, to provide better training for young people and to start promoting it more so that the teams become more successful and the viewership increases. As for why we would want to invest in women's sports where women aren't already the more commonly watched of the two genders; well, investment is usually attracted towards where there is a "gap in the market". It's the same reason why David Beckham decided to go over to the US to set up a new men's football team rather than trying to do it here. I don't think it's just about women trying to be like men; there's plenty more money that can be made from women's football than is being made already.