Chipping in here as a wargamer as well as railway modeller: the important thing from my point of view as a club chairman is to get people in the door of the hobby, and to do so while encouraging what passion they came in with, be it (as one of my favourite historical rule writers has it) 'space pixies' or whatever. The fact that they are interested in moving miniatures on a table/putting trains on a track is a far far bigger step than exactly what they model or play. If they get to do that in a supportive and friendly environment, who knows what will ensue - things rub off
There are a number of members of our club who joined us to play Warhammer, Warmachine or other fantasy/SF quasi-wargames, and many of them are now deep into various historical era (to quote one of them: "You know, I can't remember the last time I painted a figure without going to check what colour trousers it should have worn for the period"). Heck, time was when I as a railway modeller would have been happy with anything RTR in GWR green or LMS black or crimson on my proposed layout - now I'm trying to track down exactly which loco I should be attempting to model and tracking down kits for stuff that is in period People evolve, and grow into different aspects of their hobby - if we feel that /our/ particular branch is the Grail, then we shouldn't belittle or criticise, but engage.