Chumrah vs. Halakhah?

I saw this Nidah booklet posted elsewhere on Reddit.

I have never been married, but I’d like to think I know the laws of Nidah fairly well (and I certainly know them better than my Bais Yaakov classmates did when they were single).

The aforementioned booklet seems over-the-top, both in its language and in its stringency. In fact, I believe that a lot of what it says is downright wrong from a Jewish law standpoint.

Can someone tell me if my assessments are correct? Thank you.