I've always been skeptical of the Windows security model as a user but I didn't think it was that porous. Thanks for setting me straight. I found these articles explaining why it's so bad:
https://tyranidslair.blogspot.com/2017/05/reading-your-way-a...
https://tyranidslair.blogspot.com/2017/05/reading-your-way-a...
https://tyranidslair.blogspot.com/2017/05/reading-your-way-a...