A lot of us don't prewash. I almost NEVER prewash, especially precuts. I do prewash red, blue, and black flannel if it fails the hot water soak test.
You can use the search function at the top of the page. You will find all kind of prewash/no prewash topics. It's kind of a which came first...the chicken or the egg topic.
Welcom to the board. It's great here!