A lot of times there are certain techniques you can use where things work, but if you do them a different way it doesn't work. I don't know how Ducks applies that fresh horse manure, how deep or how close. Is it worked into the soil or left on top? Watered in or left dry for a while? Some people use fresh chicken manure in their garden, and chicken manure is hotter than horse manure. But they don't put a lot of it right on the plants. They tend to keep it a certain distance away. And some plants can handle that better than others.
I cleaned out my chicken coop this year and put that in the garden. By the time I plant that area it will have broken down so it's not a problem. Growing up, we'd clean out the horse and cattle barn in the fall and spread that on pastures and hayfields. Bu springtime when the grass started to grow, it had broken down so it was not a problem.
If you look at a pasture in summer you will often see certain patches of very dark green grass. That's where a cow or horse dropped a load in a pile. Initially it burns the grass and turns it yellow. But once it breaks down a little it provides so much nutrients that area really grows strongly.
Melons and squash are very sensitive to hot manure, easily burned or killed. Dad used to dig a hole and fill it with fresh chicken manure, then build a mound on top to plant his melon or squash seeds. With our wet spring climate by the time the roost were down there the manure had broken down so it was safe and beneficial.
A lot of this stuff, like that compost tea in the other thread, might depend a lot on which technique is used.