This strikes me as the right answer. Things like Star Trek and Tolkien are incredibly powerful for very small subsets of the population because their creators make risky aesthetic and narrative choices. It isn't so much that fans feel they must come to the defense of their preferred works, but that those works speak to them in rare and intense ways that are really distasteful to most people. So fans bask in the uncommon power of their fan-objects and disregard prevailing opinion. People aren't as fanatical about things like Indiana Jones or Animal Farm because their appeal is shallow and broad: everyone seems to agree that Indiana Jones is a sympathetic and entertaining character and Animal Farm is a clever allegory, but they only speak to one thing, and one thing that is widely understood. Star Trek, by comparison, is an immersive universe that goes down peculiar and deep paths that explore culture, power, ethics, and history among other things. It is not so much that all fan-objects possess objective awfulness, but they all do sacrifice wide appeal for a constrictive spiritual completeness.