Maybe I'm weird, but I don't use or interpret quotes that way (as an appeal to authority). I use quotes that express an idea succinctly or cleverly, and the point for me is the language, not the source. I'm careful not to accidentally imply that the wording is mine, but other than that quotes are pretty independent of their originators in my mind.
(But I do frequently introduce a quote by saying "as someone said" to avoid derailing the conversation to be about that person)
I agree that the language of a quotation is of utmost importance. Everything you're saying seems reasonable.
(Since there didn't seem to be one for this month, and I just ran across a nice quote.)
A monthly thread for posting any interesting rationality-related quotes you've seen recently on the Internet, or had stored in your quotesfile for ages.