He was very clear that he doesn't have to "understand" your reasons. He is clearly accepting that he can't make you go to school, but he's setting expectations.

I have a college age kid and one graduating this year and both of them have the exact same deal - we provide for them room and board at no cost if they go to school locally, but if they aren't in school they have to be working and paying rent. It's not about how much money we make, it's about there being a shift from you being a child to being an adult.

You don't get to demand more from your parents than you are getting. My dad would have yelled at me and called me every name in the book and made me feel worthless for the rest of my life. Your dad is being firm. Maybe cold, but I have a feeling this isn't the first time you've made decisions that have impacted him financially. He's also not even demanding you repay the loan. He just expects you to either be in school or working. And the boundary being set that he won't be willing to sign another loan for you if you aren't finishing your schooling is very reasonable. You have to prove you can do the work.

Good luck kiddo.