© zyxzevn

Of course some number of cropcircles are made by people. 
These are usually named "hoaxed" cropcircles. I and many other skeptical cropcircle researchers have no doubt in the fact that some people do a lot of effort to create something "phenomenal".

But the main reason why this phenomenon might be anomalous instead, is because of the FACT that some show many anomalies which CAN NOT be made by people or natural causes. 
This rules out the "all cropcircles are made by man or natural phenoma" hypothesis.

Some of these anomalies are listed in the websites above.

The strange thing is that if people create cropcircles, they sometimes get a respond from that what makes the anomalous cropcircles or experience some other paranormal stuff. So even some hoaxers admit that there is something going on. 
This respon-effect might cause some confusion by unexperienced people, making it harder for them to see that the cropcircle was hoaxed. I also suspect some skeptic teams to try to confuse the serious research by mixing anomalous cropcircles with hoaxed ones. 

Because of some weird logic many high-profile skeptics think that by damaging the scientific research, they can provide proof that all cropcircles are hoaxes. And by the way skeptics are dealing with this phenomenon, there is serious ground to believe that all "skeptic" explanations are invalid.
And I say "all" and not "many", because the basis of all skeptic theories is materialism. And as more evidence shows that materialism is false, it simply means that the basis for the skeptic believe-system is invalid. And that means we can not trust their theories about these subjects anymore.
Still we can use materialistic models and learn how the physical world connects with the metaphysical world, without any religious assumptions. 
We are back to being an observer, like Socrates.