Evolutionary biology and mud

While I was sitting near a playground in Tokyo, two things came together for me.

The playground happened to be a hippie dream. About 1 acre of dirt, some forming a hill and large quantities of rope and wood.  The rope was used for swings and high-wire lines stretched between trees. The wood was formed into benches and tables made by kids. The day I was there, there was plenty of mud and kids were sledding down the hill in the mud. There was a puddle with a rope and a tire over it.  The happiest kids were from age 3 to 10.

This kind of park is by far the most beloved by kids and the most hated by authority figures and governments.

Seeing, and remembering from every day of my life how much kids love mud and puddles I realized this is a core human attribute that must be in our genes.

While thinking about the mud issue,  I realized that I have never seen any evolutionary biologists mention this as a core human attribute.

I think very little of evolutionary biology and this is proof of position. Evolutionary biologists live in a fantasy world because there is no way for them to test or validate any of their hypotheses. We cannot observe behavior over millions of years even if there was only one ancestral species during that period.

So what can evolutionary biology be other than pure speculation. Another term for theology.

There is no evidence that humans ever lived a large part of their lives in mud. Then why do we love it so much?