For me ha Bruce Lee has become symbol first of all. Just like master Yoda and Rocky Balboa. Representing some "ideals" of wisdom, fighting spirit or whatever etc. I distinguish the symbol and itĀØs function with the real life inspiration. Yoda doesn't exist but I still quote hime at times. But as for my own style there are many more recent symbols/ideals. Could I choose IĀØd rather throw spinning kicks as good as Legendary Andy Hug, instead of like Brue Lee. But the metaphot "be like water" still means something, even if it was Yoda or some other fictional character that said it.
So quoting the symbols to me is not "appeal to authority", it is more like "appeal to a commoni ideal", which presumably is something many MA can related to, The ideal that does not exists.