A single counterexample would disprove this

Go ahead.

Torture factories don't exist

What do you mean? It sounds like torture to me: "Chickens raised for meat have been genetically selected for rapid growth. They typically reach market weight 6–7 weeks after hatching and grow so fast that their organs and bones often cannot keep up. As a result, many die from heart failure or other ailments, and countless more suffer from broken bones, lameness, and ruptured organs."

Many more kinds of torture are documented by this and many other sources that are easy to find.

I don't know how you can prove this

Here's the data.

The only way meat is cheaper than a slavery free vegan (or vegetarian) diet is if that meat comes from a torture factory

a single counterexample would disprove this. also, torture factories don't exist.

Some of these factory farms are pretty torturous for the animals, like the scale of our meat production is way too high to be clean or humane, ESPECIALLY chicken.

Local meat is still worse for the environment than non-meat that was shipped across the globe

I don't know how you can prove this

Measurement of carbon emissions is a huge one but local meat is still usually better in that aspect, and it's also the people doing the local farming have closer to living wages usually.