The reason no scientist says plants experience pain the same way is because there is no way to know for certain due to a communication barrier. The only reason we 'know' animals experience pain similarly is because they can scream in a way we can hear and is distressing to us. While the articles I mentioned initially talked about how plants do something very similar, but with exuding chemicals and screams we can't hear. There is evidence that it is a very real possibility and shouldn't be discounted simply because hurting an animal makes us feel bad but hurting a plant does not. Arguing otherwise is the equivalent to saying just because you can't hear someone scream means they don't feel pain, which is an obvious logic flaw.
In regards to your metaphor, I thought I was fairly clear. Putting a kitten in a blender seems like the worse option to people, because we feel empathy for kittens, they're pets and display emotion audibly. Mowing the grass kills many plants, while the kitten is just one kitten. Along with what I was saying about how plants are on the same level as non-sapient animals, that means mowing the grass is a worse moral crime than putting a kitten in a blender.
Oh, and humans ARE kept in factory farms for their flesh. It's called the US minimum wage. And that's just the obvious/witty answer without going into black market slavery or totalitarian states.
