The title of the thread asks if the sport is elitist. I think the answer is clearly, no.
Like any sport (beach volleyball, Grand Prix racing, bicycle motocross, etc. etc. etc.) it attracts followers, or fans, with the full range of enthusiasms, which leads to the question posed in the body of XXX's first message in the thread: are we, the 'fans' of muzzleloading, elitist?
That's a different question. People who have an interest in a particular pastime (fans) are to some degree elitist simply by virtue of that interest; they focus quite naturally on what they enjoy doing. A percentage of those fans are obsessive about their interest, and they would seem to personify the 'bad' definition of elitist - they tend to look down on those who do not share the full measure of their obsessive viewpoint.
We'd all like to think that those obsessive fans do not represent the rest of us and the sport in general, and I believe that's true. So, to answer the question in the body of the post: we are elitist in the sense that we are enthusiasts, some more than others, but overall, with a few exceptions, we are not the elitist that derides those who do not share our enjoyment of the sport.