Oil Painting -Don't Listen To Schooling!!!

I don't understand why many schools insist students need to use mediums and turpentine to paint with oil paints! It's not true. It's toxic and a headache. when you want to wash your brushes all you need is DAWN dish soap or Murphey's oil soap. I do have a glass jar 1/5 filled with terpenoid natural in the green can and is citrus based to soak my brushes after painting till I get to the sink to wash which is like a month but that's it! If anyone has anymore questions about this feel free to ask. I also find Oil paint is cheaper to paint with than acrylics.