I have not read Keynes other than when he is quoted in Austrian circles. However, contemporary Keynsian sympathizer Paul Krugman does not sound at all like he would agree with your teacher.
Krugman is famous for pushing the notion that the U.S. during FDR, Japan during 1990s, and U.S. during Obama and Bush did NOT RUN BIG ENOUGH DEFECITS to counteract the respective recessions. If he truly follows Keynes, it follows that Keynes would support major stimulus packages.
Hopefully the experts will weigh in!