Two wrongs don't make a right.

Of course you should remind your employer of their responsibilities towards you but as a teacher you have responsibilities towards your students. If, as the posters who stated they would just play DVDs all day had previously suggested, you have to be a creative professional educator to work in a public school, then why couldn't they use their skills to put together a genuine lesson? This doesn't mean your grovelling or appeasing your boss, it means that you're acting with a degree of professional integrity both to yourself and your students.

When you met the problem with your current employer you didn't sit in the corner and sulk about it, you raised it with them and a solution was found to ensure you could continue to work effectively. In the past you've posted about your experiences with a university in Qingdao where you raised concerns about accommodation that couldn't be resolved. Your response was to leave that position. These appear to be two good examples of what to do in such a situation i.e. open a dialogue giving the school a chance to do the right thing but if you really hit a brick wall then leave - the job market is weighted in favour of foreign teachers so you're right to say that you don't need to put up with any rubbish. However, when seeking to resolve a situation with a school surely your position is enhanced if you are able to present yourself as an asset to the school (again I'm not talking about grovelling or appeasing but simply doing the job you were hired to do). Showing DVDs in class does not give the impression that you are such an asset and does not help you to resolve issues with your employer.