I had the same question and did not see any new replies in the last 3 days so I asked ChatGPT and it seems to have helped me a little bit:

Here's why "some" is considered a superset of "most" and not the other way around, and similarly, why "most" is a superset of "all."

"All" versus "Most"

"All" refers to the entirety of a set. When we say "all A are B," we mean that without exception, every member of set A is also a member of set B.

"Most" implies a majority but not the entirety. Saying "most A are B" means that more than half of A's members are in B, but not necessarily all.

Because "all A are B" guarantees that every single member of A is included in B, this statement naturally implies that "most A are B" (if all of them are, then certainly more than half are), and it also implies "some A are B" (if all are, then at least one is). However, "most A are B" doesn't imply "all A are B" because "most" allows for some members of A not to be in B.

"Most" versus "Some"

"Some" is even more inclusive, indicating that at least one member of set A is also a member of set B. This is a very minimal requirement compared to "most" or "all."

When we say "some A are B," we're only committing to the existence of at least one member of A in B. This is why "some" can be seen as a superset in this context—it requires the least specific condition to be met and is thus more broadly applicable.

"Most A are B" naturally implies that "some A are B" because if more than half of A are B, then at least one A is B. However, "some A are B" does not imply that "most A are B" because having just one A in B does not satisfy the condition of a majority.

Summary

The implication direction (subset → superset) reflects the inclusiveness and specificity of the claim:

"All" makes the most specific claim and thus implies both "most" and "some."

"Most" makes a less specific claim than "all" but is more specific than "some," implying "some" but not "all."

"Some" makes the least specific claim, implying neither "most" nor "all."

This hierarchy is about the logical strength of the statements: more specific claims (e.g., "all") carry more information and thus have stronger implications than less specific ones (e.g., "some").

So it seems not very intuitive to me either, but because if all members of a set A are in set B, then that must imply that most members of set A are in set B, which then implies that some members of set A are in set B, most is the superset of all and some is a superset of most.

Late reply, but in case it helps:

Just because linguists have conducted many comparative analyses of traditional languages from various regions and eras does not mean they found meaningful results that point to the fact that human communication is a universal phenomenon that has existed across different civilizations over time. It is possible that they conducted these studies and did not find results that support the conclusion. Because of this, they are two separate statements.

Since I see no reply from a teacher I'll attempt to provide another explanation here and hopefully it helps:

Most well-stocked intellectual places showcasing a wide range of books on various subjects does not explain why all libraries and bookstores are intellectual places.

Why?

Premise 1 makes a statement about libraries and bookstores (that all of them are intellectual places), and Premise 2 makes a statement about most well-stocked intellectual places and their characteristic (having books on various subjects). Premise 2 does not tell us anything about libraries/bookstores, nor does it tell us anything about why libraries/bookstores are all intellectual places.

I think the important thing to consider here is that even if we might /personally/ believe (based on our experience) that most libraries/bookstores are well-stocked with books on various subjects, this does NOT make it true in this snippet, because it is not stated. It would be a mistake to insert that assumption ourselves.

The sentences simply state something about all libraries/bookstores, separately state something about most well-stocked intellectual places, and then separately state a conditional case for what makes something NOT well-stocked. We don't know in this argument if libraries and bookstores are indeed well-stocked or whether MOST libraries and bookstores are well-stocked. We also don't know anything about whether libraries and bookstores are disorganized or not.

Hope this helps explain it better!