From a purely commercial viewpoint, and considering where best to offer things for sale, it makes sense to use channels that provide the greatest degree of interest. For minerals, I reckon that's mineral-based websites. This is primarily a mining history and exploration website. That doesn't mean we don't collect minerals, but, as you can see, there are those who have reservations to some degree. So, from a purely commercial viewpoint, this is not the best site for it.
As the main interest here are exploration and history, it provides a much better opportunity for selling books, exploring kit, and the like. To make best use of this site, one is looking at advancing one's knowledge and understanding, so the gain tends to be literally academic rather than material.
There is really no need to confront the site with accusations of bigotry - you can see that we are basically a friendly bunch with a wariness in some quarters. If I was responsible for a historical site where funds were required to enhance it (and as it happens I am), I would most likely use this site to direct interested people to a place where such promotion was more appropriate perhaps. In my case this isn't necessary as it is site entrance fees and public donations that more than provide the necessary funds.
Like it or not, mineral sales do provoke passions, and that is a fact of life. Roy's concerns were that because of this, one has to be wary of what has happened in the past. In the case in question here, it is a rather unusual instance and I can sympathise with the protagonists who have no problem with it.