I totally agree. It happened with me as well.You are not being judged by your ideas in the IELTS writing test. It's all about word choice which should be accurate, diversity of grammar (simple, compound and lots of complex sentences should be used), coherence throughout the whole essay, and finally task response. I disagreed with the statement and wrote that governments should make TV advertisements to raise public awareness. It's not about your personal idea at all. I scored 7 two times in my past IELTS experiences and my ideas where both really simple and not completely logical, so there is no correct idea in writing.