Which instance of "random" do you think should have been pseudo random?

The instance I quoted. But as I said the point is trivial.

Are you saying that the use of randomisation in software is always a misttake

I don't think I used the word "mistake", at all. I didn't even imply that it's sometimes a mistake, let alone always.

It is true that a random number is no good in itself, but equally you can't solve every problem with pure determinism.

Please name three problems you can't solve with determinism but you can solve with random-number generators. Besides encryption which depends on secrecy and therefore depends on not knowing what will come out, I can't think of any.