Furry is definitely the most maligned fandom out there. Probably plenty of reasons. Most people associate talking animals with cartoons for kids, so adults who like that stuff are suspected of gross immaturity (at best.) A related issue is the juxtaposition of imagery that most people see as child-related with adult (sexualized) themes and situations. Maybe it's that the hard-core sci-fi fandom geeks need an even smaller, more despised minority that can be seen as lower on the social totem pole to make themselves feel less like rejects. Or maybe it's something about people who are drawn to the furry fandom that invites abuse, like chronic low self-esteem. Or some combination of all of these?
Whatever the cause, what should probably be seen as a fairly harmless pastime somehow pushes all sorts of ugly emotional buttons for a lot of people. Yeah there are people who get their jollies while dressing up in character costumes, but it's hardly the weirdest fetish I've ever heard of, and it's probably vanishingly rare. There's that one lady who always wears her Star Trek uniform even to work, and talks like she's really in Starfleet, but that somehow doesn't paint all sci-fi fans as kooks in the public's mind.
And just to be perfectly clear, I am absolutely not
saying that sci-fi fans are social rejects or that all furries are pathetic losers. That would be absurd and worse, incorrect. I'm talking in a broad sense about feelings and perceptions, not objective reality as it relates to these things.
If I were speaking objectively, I'd feel obliged to point out that human interest in human-animal hybrids goes back to prehistoric times, and that humans assuming animal shapes or communing with animal spirits is part of nearly every society's mythology and cultural tradition. Human interest in assuming the shape of a war robot from outer space is a much more recent invention.