The idea that we 'lack humans' in a world where so many live a life of struggle that these technocrats can only imagine, is disgustingly absurd and needs to be called out. Who exactly are they thinking of here? Do they really expect us to think they care about the people involved? I will show you that they do not.
I believe that Elon Musk's tweet gives me reason to think that there's an uncovered agenda. Maybe he never wanted anyone to point at him if he had said 'the world's population is too much'. I could see wisdom and craftiness in Vitalik's tweet not wanting to implicate himself either. Like you had pointed out above that the world doesn't lack humans but the world lacks the adequate infrastructure to take care of the raising population. Only Nigeria, for instance, has about 200 million people and 60 to 70% unemployment amongst young people. People in Sub-saharan African needs help and they're talking about more humans. I think too much money and information becomes a problem to rich people. For the matter of synthetic womb and the inequalities between men and women in the women. I think there's freedom of choice to everyone on planet earth as propagated by the tenets of democracy. If choice is free, then the matter of inequalities between men and women should not be said at all. One can decide not to marry or give birth and also avoid to adopt a child give birth through reproduction between a man and woman. By the way thanks for stressing yourself to bring out this great points to my view.