The fact is, people aren't born equal. Some are more intelligent than others. Some are more attractive than others. Some are more healthy than others. People will never be entirely equal, and life will never be entirely fair.
I agree--of course, everyone is born with different personality traits, physical traits, and family circumstances. That's unavoidable. Shouldn't everyone have the same rights and opportunities, though, such as basic human rights, equal education and career opportunities, and equal justice under the law?
That said, I can see how bringing this issue to the forefront in the UK and Commonwealth nations can spark a debate about a whole host of thorny issues, which may include whether younger children or even extended family should have equal rights to inherit the throne (not to mention how that individual should be chosen), the irrelevance in modern times of the original underpinnings of monarchy, and the ultimate question of whether it should exist at all. It is a needed debate, whether it's welcome or not.
At a time when many other, more important issues are demanding immediate attention, I think this debate should happen at a different time for the UK public and government. Equal primogeniture is far from a pressing issue, and affects only the royal family (or perhaps also the aristocracy), so it shouldn't really be a matter of concern for the gov't. at this time. Basic human rights should be addressed first.
Of course, that doesn't mean royal enthusiasts can't debate it here--I just mean that it should not be a matter for national debate quite yet.