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Hobbyist communities are often built and maintained by a handful of hardcore power users who end up dragging a bunch of their bad, wrong and occasionally dangerous ideas into the mainstream. If they are questioned on these ideas they react ferociously, because they have spent a long time defending them and now they are ego issues.

It's a real double edged sword because on one hand these people really do keep hobby communities alive, but their stubbornness often ends up putting the community at odds with actual expertise.