Hey lil
I think you are definitely right to call your student out on absolutist terminology. I'm assuming your student is referring to human social groups, but I'll make the quick point that not all social primates have a clear and distinct hierarchy (e.g., orangutans, gibbons). In humans it is hardly true that ANY social group has a clearly defined alpha position. It may be true that within any social group there is some implicit or explicit stratified hierarchy, but that hierarchy can be diffuse and decentralized. Also, it depends on the "level of the social group" we are discussing. Furthermore, it is extremely problematic to say that there is always competition for an alpha position. Largely, this distinction depends on context. For example, within a class there are students and one teacher. This is a social group, however the students are not directly competing with the teacher for the alpha position. The teacher may have to deal with external competition outside of the immediate social group (although not necessarily), but like I said it depends on context. Let me finish by saying that I understand your students point, but he is shooting himself in the proverbial foot by making a generalized statement (like kurmit aptly pointed out). Added thoughts (I was on my iPhone when I wrote the above): If your student wants to be stubborn and keep the sentence largely in tact he could do the following: "In any traditionally defined large-scale human social organization (e.g., band, tribe, chiefdom, state), distinct hierarchies with a clearly defined alpha position seem to develop the large majority of the time."
It's rarely a good idea to use absolutes. I would imagine this is especially true in an academic setting. FYI, your shout out to kurmit didn't take because of the "e" instead of the "u".