I think the best way to evaluate claims like this
@hdan is to try it yourself. There is so much online information about gardening, much of it contradictory too. It's easy to get lost in the tsunami of information. Some cautions don't really apply to backyard gardening, so don't let it intimidate you. I've never rotated crops myself or separated cruciferous veg. When I first started gardening I was starting at -0, and had no experience, so I used to stress quite a bit about things and then someone said to me, 'Relax. They're plants. They want to grow.' And I have honestly found that to be good advice. You are working with a good partner with plants, because they want the same success you do.