Why are there so many mistakes in this website?

There is a good reason.

Writing is similar to translation.

The basic guideline for the Grossman Translation Method is to throw the information on the screen or on paper, and then to edit the material as a second stage. In this way, the process of translating is similar to writing. Both writing and translating should be "thrown" onto the screen, and edited subsequently.

That is precisely the way in which this website was prepared. The basic information was thrown onto the screen. Actually, it was dictated into a recorder and then transcribed onto the screen.

Many of these transcribed pages and links have not yet been reviewed for the most elementary mistakes. This is a slow process under the best of circumstances, and even slower when working on forty websites simultaneously.

That means that you should relate to this website as you would relate to any other work in progress. Suggest changes and corrections, and then check the website in half a year.