There' a difference between 'deciding not do procreate' and 'having an obligation to not procreate'. It's the same as 'I decided not to steal' v. 'It's morally wrong to steal'.
This whole article is centred around a moral argument, i.e. 'it's morally wrong to procreate'. So, you're right, I am making a case of a 'universal ideal morality'. But I don't think you and I would think this wrong.