Somebody saying "I am a mermaid" would be looked at strangely too.

Probably because old folks know that mermaids are a myth and don't identify as mermaids ( although ai think I saw a docuseries about a 30ish year old thinking he was one) Where as furries bleed the line between what might be fetish realm, and what might be some people actually believing/thinking they are a furry animal--which would be considered a delusion.

Probably because furries are a fetish and mermaids come from mythology

I mean, the point of a mermaid isn't that it's a sexy looking fish, it's that other than its tail, it looks like beautiful human women. In some stories, sailors don't even realize they're taking to mermaids because their tails are underwater. Also, mermaids were generally considered bad omens or malicious entities, and when they did seduce humans, it was usually to kill them, so it's not like the folklore was very pro-mermaid sex.

Being with a mermaid is also an outlandish idea

Because people didn't dress up as mermaids and go to cons and express how deep down inside they truly are a mermaid, and have a high likelihood of fucking someone else who also felt the same way.

Bist because the idea is older doesn't make it any less weird.

To be fair, I think people looked at the folks who were into mermaids as outlandish too. "Been around for a long time" doesn't mean the same thing as "totally accepted socially".

Now ask them about reversed mermaid

I went to dragon con one year, people were dressed in all sorts of costumes even though it's not a furry con. And I know the hotels where the con is are incredibly hard to book. That said just once I want some senior executive to accidently book a room in one because he has some meeting with a potential client of something and just so happen to click it at the right time.

He shows up and is completely bewildered by all the people in costumes. "you'll never believe it mark. I rode down the elevator with a robot and I swear to God... Tiny from Bob's burgers"

Furries aren't as recent as people tend to think either I might point out, the subculture has existed in some form since like the 80s to my understanding, it's just more popular and visible these days.

My brother in Christ, werewolves existed for at least 150 years and shape shifting goes back hundreds more. A beast that becomes a person... What could that possibly be for? A person becoming a beast is easy and the not weird part of folk history that didn't upset any kind of established morals. Violence is a part of life. Hot wolf dick that escapes into the night after making sweaty sheets? More difficult to keep as an oral tradition. Well, in stories at least.

It's like one of those irregular verbs. I've got a cool fantasy, you're a pervert, he's in jail, etc.