I have a question regarding the nature of the conjunctions "for" and "because".
The former is known to form part of the famous acronym FANBOYS, that encompasses the most common coordinate conjunctions, whilst the latter represents one of the subordinate ones. Still, they appear to share the same semantic properties and express the same relation.
The dude is not coming because he is mad at you - the second clause gives the reason for the dude's not coming => it is dependent;
The duke is not coming, for he is no more - same relationship, only slightly more poetically put => it is dependent.
I'm sure these conjunctions have been "separated" for a good reason, so could you please explain why we consider "for" to be a coordinate conjunction?