Because the almost absolute majority of people who know vore exists (which is honestly a rather small percentage, I'd wager) but aren't into it don't understand what it actually is. They assume it's on the same level as wanting to be torn limb-from-limb and consumed by a cannibal tribe in Papua New Guinea or something, or those with only the faintest hint of what it is associate it with furries and cringy DeviantArt shit because certain people who aren't into it claim "expertise" on the matter and say it is. It doesn't occur to them that it's entirely a fantasy, it's not possible for a human being to eat another human being alive (except for cannibal shit), and it's essentially a buffet where you can pick and choose what you want on your plate.
The more you get into vore, the more you realize that a lot of other fetishes play into it and you can essentially come up with any variety of scenarios. It doesn't even have to go the full mile, you can just enjoy the part with the mouth (mouthplay), or you can come up with some other way for vore to happen such as breast vore. And for the most part, there's lots of different "predator/prey" combinations you can have.
If you're not into furry stuff (and hey, if you're into furry stuff, then you do you, no problem) but you're curious, don't let the fear mongering get to you. There's lots of content out there on sites like Eka's Portal and occasionally on /d/ on the other chan that you can go through. A lot of human/humanoid predator/prey content to enjoy. And if you decide it's not for you, then that's that.