Dear all of you,
Most New Year’s resolutions involve weight loss so this is not meant to offend. When I think of all of me, a resolution or least some resolve to lose a little weight may be in order for this blogger. Not a lot, just enough to make my new jeans more comfortable. Now, back to you, I mean, all of you.
According to the Merriam-Webster dictionary, “of” is a preposition used as a function word to indicate the component material, parts, or elements or the contents <throne of gold> <cup of water> <all of you>. When someone attempts to greet you in the globally inclusive way, all of you, I doubt they are referring to the component material or parts of your corporeal presence. They are just ignorant or being lazy.