The problem is that most people who don't cycle when asked will rationalise it with some off the top of the head reason when very probably have never considered it. So you end up not with the reasons but the popular excuses. Then you can easily end up chasing ghosts.
Why don't you cycle?
It's not safe.
We've sorted that so now will you cycle?
But I might get wet.
There's good rain gear available
Yes but it's expensive
You can get some good stuff cheap from Lidl
Yes but what will people think if the see me in it
Etc
If you don't want to do it there are a million excuses you can come up with not to
Spot on. I've worked promoting cycling at public try-out events, and heard it all.
There are some who would like to, and just need to be helped with information - perhaps having their eyes opened to the range of bikes, trailers etc that make life easy. Just knowing how much you can carry in a basket is enough for some. Others have only ever ridden crap bikes, and riding something well set up is a revelation.
There are some who simply aren't interested, and happy to say so.
But there are lots who know that really, they 'should' (and could) cycle, but don't want to. But 'I don't want to' sounds weak, and childish, so they find a 'valid' excuse. Knock that down, and they'll find another, and another, and another.... Sometimes, along the way, they will realise that actually, yes, maybe they can do it, and sometimes, you'll never convince them.
Surely, the best thing is to listen to a wide range of people, of all levels of knowledge and experience, and do a decent job of understanding that range of opinion and what it shows. It would be daft not to listen to those with experience, because it's highly likely that a lot of them were once people who didn't cycle too, so they know just how it feels to go through the learning process.