I think 'soapy' means different things to different people. Coriander leaves, to me, tastes repellent. More like a strong floor cleaner or a bathroom spray than soap, really. A weird, chemical sort of taste, like food that's been contaminated with something.
By contrast, I love Turkish delight, Parma violets and lavender biscuits, which I also hear a lot of people describe as tasting soapy. To me, they taste floral and delicate.
Weirdly, ground coriander tastes absolutely fine. It's just the fresh leaves that are utterly rank to me.
I'm not a fussy eater at all - there are only really two foods that I absolutely hate, and coriander leaves is one of them. The other is raw tomatoes, which I also think have a chemical, non-foody taste. Cooked tomatoes are fine though.
It's weird that I can happily eat anything, including things that lots of people think are totally gross, but gag at a raw tomato or a sprig of coriander.