The title of this thread touches on some important topics of cryptography.

1) What do you mean by true randomness? Don't we already have true random generators? Do you mean that our supposedly random numbers are chosen predictably?
2) Why is your way more random than ours?

I don't have much to say, but this. Human moves are generally predictable, so anything the human knows he's doing can be predicted on way or another. So, what's unpredictable? The exact opposite:  Roll a dice!

While it's a procedure in which you can calculate the final result, you don't, because it's difficult. So, for you, who's rolling it, it's unpredictable. It's a great source of randomness if the dice is properly made. (Each side is a 16.6%)