These topics are subtle and the current fashions among some social classes in some regions of the world cannot be considered as something more than mere fashion

These topics are subtle and the current fashions among some social classes in some regions of the world cannot be considered as something more than mere fashions. For example, that "obvious and easily observable health benefits of being vegan" are related to the avoidance of processed foods and heavily unbalanced diet, rather than avoidance of "animal flesh" or dairy products themselves. This is just the confirmation bias and similar factors at play. Those, who have studied human physiology, not just cellular metabolism, which is also important, could tell that the problem is too complex to be dealt with by silly slogans like "avoid red meat". There are many subtle ratios involved, not just an ability of a particular enzymes to convert a particular molecular structure into molecules involved in the metabolism and support of the homeostasis, but the ratios among these processes. The balance is what is important. In other words, "substituting the protein sources", is not that simple as it seems. There is no scientifically proven reasons to avoid dairy products, except for individual cases of lactose intolerance, while there is a consensus that the food industry is the cause of the problem to which veganism seemed to be a solution. Tribal eating habits is a quite interesting topic, btw. As for birth control, this is quite another topic, which, perhaps, cannot be discussed in this context. For some members of so-called "urban-middle-class" in some region of the world the policies of forced birth control are acceptable, while in other societies there are quite different reasons about how many children should a family have and why. And, of course, it is not for some "vegans" to decide what other people in other regions of the world should do.