Because you're cursed with that gene. A small percentage of the population has that, I'm sorry for your loss.

I grow cilantro and save the seeds (coriander) for cooking. My daughter claims it tastes like soap and so do other family members.
I didn't think so!
There are various claims as to why it may taste like soap. I don't know if it's genetic since not all of us in my family agree.
Maybe it's like other foods that some of us like and others don't... a taste preference?

I love cilantro ! A good pico de gallo is to die for !

It’s the lemony flavor probably plus those who hate it have a genetic marker linked to cilantro hating. The seeds of cilantro can be used to season fish or chicken to make it taste lemony.

Because you have a genetic disposition to perceive the taste of a certain aldehydes in cilantro as soapy. Not everyone has it, so to me, it doesn’t taste that way. It’s around 20% of the population that perceives it that way.

I thought I'd read somewhere that it was often an indication of being a 'super taster', able to pick out flavors and subtle flavors and scents that not everyone could.

It doesn't. It tastes delicious! "Dennis The Menace."

Why isn’t soap made from cilantro?

A small % of the population seem to have that proclivity to taste it like soap.

You need to rinse it out completely, after you wash it out using soap.

What Aidolovemostofyourthoughts said.