I will have to agree with the dead comment by @leafboi, it is not that every animal can live harmoniously, indeed every animal is in competition by the laws of natural selection, and each animal can be seen as the outlier in its species. In the case of humans, there may be multiple paths to success, but it may be that many of them lead to failure while producing certain outliers.
Unrelatedly, does anyone know why certain comments immediately become dead, they don't really seem to break any HN rules but I see often that some comments die quickly.
As human beings, moderators have their own preferences which exist beyond the HN guidelines, and are not meta moderated, except in the aggregate.
When a comment becomes dead, it's because some mods chose to vote it down, and fewer mods choose to revive it. The net effect is an expression of the prevailing culture.
Your question about why this sometimes happens "immediately" is an interesting part of the dynamic.
Unrelatedly, does anyone know why certain comments immediately become dead, they don't really seem to break any HN rules but I see often that some comments die quickly.