Why are circuses so often evil?

Nobody trusts them.

Da da dadadada dun dun circus,
Da da dadadada dun dun afro,
Circus afro, circus afro,
Polka dot, polka dot, polka dot, afro!

Their "mystique", or "magic" of circuses make them a good place to plot odd things. There's a sense of wonder about them. That kind of atmosphere seems to fit that sort of concept. People writing stuff like that can see how it would fit, so they do. Just my thoughts on that anyway.

Do you know how to kill a circus...?

Shady people traveling from town to town under cover of darkness, transporting dangerous animals and a caravan of freaks to set up rickety rides and rigged games to be 'enjoyed' to the sound of creepy calliope music and the smell of fried and sugary foods that would probably make any health inspector cringe. And yeah, clowns.

Other than that, good times, man.

Clowns. /jk

But seriously, circuses are liminal places where their members come from the fringes of society. They have no roots in any particular geographical place, but variations of circuses exist amongst most cultures. Their show's often have a dual purpose of filling with wonder as well as fear.
All that stuff is gold, if you're searching for settings as a writer. I agree that it gets used a little lazily, but it can be a great setting if used right.

Have you seen Stephen King's It?

Because clowns are EVIL

MCL

dont care bout clowns^^ for me its more the animals
people which are use animals like this can only be monsters

I dunno... maybe it's because they literally have no other reason to show us a circus in a game (or movie for that matter) unless it's in some way significant... and unless it's evil it's not significant. ^_^'

It's because they love llamas too much. They can't resist keeping a llama in custody for their pervert circus business. Luckily, there are still nice people to fight against evil.

It's because using gypsies for that spot is considered racist now. And on top of that, rambling tinkers, mountebanks, and peddlers just aren't a thing anymore. So, the only STRANGERS COMIN' TO TOWN left is the circus and the foreigners.

because before in circus main events were something like "extraordinary three legs woman" or dwarf with 2 penises etc. People are scared of things which are not "normal"
So if it's "freak of nature" it can't be from god=it has to do something evil.

Traditionally it has been home to "freaks", people with "weird" abilities and exotic animals. They "appear" over night, and for the next few days they "invade" your town, then "disappear" again over night, moving for the next town.
This gives them a mystical aura. It portaits the "different", the "scary".
And fo course clowns... you can't simply pretend they're not evil.

No one likes me. ;___;

Don't they beat the animals to train them to do what they want?

Not sure if you're ready!
[NSFW] Trailer with EN subtitles (where they answer your question)

Clowns and Juggalos. That is why circuses are evil.

Well of course they would use a circus to sneak into a city, just look how many they can fit into a clown car. Now imagine if they made a clown military troop transport truck. They could potentially get thousands of clowns into the middle of a city with just 2 or 3 vehicles!!!

As long as no clown figures this little bit of info out we only have to deal with them 1 clown car at a time.

Circuses Are GREAT For Getting Rid Of Dead Bodies! All Those Hot Dog Stands...
...

Unless You're InTo Peanuts... Then Stick To Your Peanuts And Don't Be So Snoopy.

I think Patton explains it well.

It's a type of curse that spreads all round (circ).

I think it probably has to do with the fact they treat their animals like shit