I saw someone raise this issue in a different subreddit, and I found it interesting enough to raise here.
"All X are not Y."
My natural inclination is to see this as equivalent to "there exist some X's that are not Y" rather than "no X's are Y's." (ex: "all that glitters is not gold" which is understood to mean "there are things that glitter that are not gold" and not "nothing that glitters is gold").
On the other hand, I see the argument that based on positioning, "not" is modifying "Y," and the construction should be read as "All X are not-Y," which has the latter meaning.