Both are essentially aggregators of not-for-profit university lectures. Education is a weird thing. We don't know how to do it well, and we don't know how to ensure it is taking place, but every for-profit university (new online ones possibly excepted, I don't know) is designed to take as much money from possible from consumers who are, by definition, uninformed.

Non-profit institutions have a goal of education and/or research. For-profit education is designed to soak the uninformed, with the exception of education that is for person A, but purchased by person B. In that case, it is possible for person B to be an informed buyer.

Basically, the market for education is subject to many market failures. For-profits exploit these to the detriment of all.

They aren't accredited.