ProVobis didn’t say it was optional. He said they’re options. Why do you have exceptions for hymns set to propers but not hymns not set to the propers? What’s absolutely clear is that the propers aren’t required. Your reading would render options 3 and 4 superfluous.
Well, with all due respect to ProVobis, his words were the following: “…they (meaning the propers) are options…” So I guess technically, he did say “they’re options” as you claim, but “propers are options” seems to me to clearly mean “propers are optional.” Perhaps ProVobis would like to clarify what he meant. ProVobis, did you mean that propers themselves are options (as in, you have the option whether or not to do a proper), or did you mean that for each of the different propers, there are options?
I can’t really respond to the latter part of your post, johnmann. However, I would like your opinion: what do you think they mean by “chant”? Hymns aren’t chant. The GIRM clearly says “chant”, even in 3 and 4.
BTW, the Latin word in IGMR is “cantus” so it could be song, chant, or melody. But it shouldn’t make any big difference as to the action.
ProVobis, I clicked on that link you gave and right at the top it says 2002. Someone may correct me if I am wrong, but we go by the most current GIRM version, which I think is 2011. And as I mentioned before, the translation was changed from “song” to “chant”.
As I really am not too familiar with what interpretations of this have been thrown around, I may be unaware of an interpretation which says that hymns are chant. That is, hymns as are common today; there are Gregorian chant hymns, but those are rarely sung today. Anyway, that was all a long way of saying, if you or anyone knows of an authoritative document after the new 2011 GIRM came out that supports the idea that the modern hymn is a chant, then I would be happy to acquaint myself with that document.