From F-1 visa to green card...?

It's not BS. Your four years of residency as an international student do not count towards meeting the state tuition residency requirement, usually one year. The clock starts ticking from the date of your green card. The reason for the one-year requirement is so that US citizens and green card holders don't jump over the border to another state just to go to college. Tuition at state and local colleges and universities is subsidized by state, not federal tax dollars. Some states fund their schools more generously than others, and understandably, state residents don't want to fund the education of people who moved there just to go to school. The $25,000 tuition you paid covered the cost of your education only. Meanwhile, the parents of your fellow US citizen and LPR students have been funding education for many years with their tax dollars. Be patient, wait a year, and you'll be eligible.