well your premise is flawed... you're not going to get a pattern like that by trampling - you might be forgetting that human beings have hands and can use them to manipulate things.... weaving some crops into a complex pattern is some hoaxers trying to take things to the next level. These groups compete with each other to produce ever more impressive designs.
Yes a small % may not be man made - i.e. simple circles formed by weather etc...
But anything which has actually been designed, laid out... you'd have to be a bit damaged in the head to start dismissing the fact that there are groups of people who go out at night and create these.