The alpha-beta male distinction is a term used in zoology applied to animals which generally have some form of social structure like pack mentality, often patriarchal dominance which influences mate selection. In primates it's found in various species, but not all primates, and certainly not all species, exhibit some form of alpha-beta social stratification in regards to sexual selection.
In fact, primate social structures show great diversification -- some are matriarchal, some are egalitarian, and of course some are patriarchal. The alpha-beta theory in humans is based off an inherent idea that human society is and must be patriarchal; it is the idea that dominant males rule over both inferior males and over any females in their social circles, but his simply doesn't have to be, nor I would argue is it, the case in contemporary Western human culture.
The perpetuation of the idea that there are alpha and beta males in Western informational mediums probably influences women and men alike to believe that there are such social stratification in humans, thus having the effect that men exhibit competitive behaviors and are taught to be assertive and dominant and competitive while women are taught to be submissive and to sexually aspire most to mate with what is socially considered a ''dominant male''. But actually, studies show girls can be as dominant and aggressive as boys, and boys as placid and gentle as girls. Naturally, girls and boys are fairly equal in temperament, and what we have as adults is a result of social conditioning.
Of course, there are grounds found in the study of human societies both past and present to indicate not only that the definitions of what is a ''dominant male'' change dramatically -- sometimes incorporating diametrically opposite personality characteristics (in many Eastern cultures self-contentment and humility are more desirable than insatiable drive and exuberant confidence, and even between American society and British society there is a discernible difference in the level of brashness in men) -- but that in fact many societies in human history did not exist upon ideals of patriarchy, rather egalitarianism or even matriarchy.
Modern Western society does hold a general idea of what makes a desirable mate but this idea is by absolutely no means consistent across all human cultures, therefore it should not be considered as the standard sexual selection process in all humans.
Alpha-beta value attribution may very well be the natural selection process of humans, but we don't have any way to know for sure.