Scott Brown may Indeed be a 'Celtic legend' , in which case say so rather than the frankly purely driven by emotion , statement, "Legend, no more to be said".
Personally, from my boyhood days I would cite the two Bobbys, Murdoch & Lennox, Tommy Gemmell etc etc as 'Celtic legends' but I wouldn't insist, as you appear to do, that all other fans of all other clubs have also to accept them as 'legends'.