I may have found the post by Michael Nielson I was looking for... on Hacker News!
https://news.ycombinator.com/item?id=666615
In particular, this piece of advice he gives still rings true to my ears:
Often, when struggling with a book or paper, it's not you that's the problem, it's the author. Finding another source can quickly clear stuff up.
Would anybody be able to provide the blog post I believe we both read, which says almost exactly what Iv wrote? I could have sworn Michael Nielson wrote it, but I was unable to produce it last time I searched. So I am following OP's advice and am asking here. :P