DS7's first grade was similar - everyone read the same material mostly. There was open reading time where there was a little differentiation, but that only happened a couple times a week for a short period of time.

The teacher tried to differentiate after a conference when I complained. I even gave her some book suggestions. She ignored my book suggestions and gave him a book he already read in kindergarten (which I told her). She rarely followed up and he languished all year. She "assessed" his reading level at the beginning of the year the same at the end of the year. Despite obviously progressing through many levels of reading at home.

Anyway - I tend to agree with this article. And I thought a lot of the comments from parents were very interesting!