I think this list is completly unreliable. Using ratemyprofessor.com has to be the worst idea ever because, usually, people only rate professors if they disliked the class. Also, classes with more students in them are more likely to get a rating on that site.
The list also seems flawed because it doesn’t account for all asepcts of professorship. There’s teaching, research, service, adivsing, mentoring, etc. etc. etc. Those things are all very hard to rate, and I doubt it was taken into consideration that someone might be an amazing professor, but that mentoring takes precednece over teaching in their position.
Finally, I do believe not all schools are equally considered in these ratings. There’s no way they could be because I think it would be impossible to impartially rank every professor at every college. It’s even impossible to do it at a state level as I’ve seen average professors get “best professor” awards over people that are just amazing at their jobs.